KR20000015887A - Photo-addressable substrates and photo-addressable side-group polymers with highly inducible double refraction - Google Patents

Abstract

PURPOSE: Rapidly photo-addressable polymer as storage media can be achieved by changing optical anisotropy selectively and partly. CONSTITUTION: It is possible to produce extremely rapidly photo-addressable storage media from inherently slowly photo-addressable polymers by irradiating the substrates over a large area with a light source suitable for conventional inscription so that an optical anisotropy, i.e. a double refraction with a preferential direction in the plane of the substrate, occurs. If the substrates prepared in this way are briefly intensively irradiated, the pattern is inscribed extremely rapidly and permanently.

Description

Photo addressable substrate and photo addressable side chain polymer with high induced birefringence

The present invention relates to a method for rapid recording of optical addressable substrates, substrates produced by the method and the use of such substrates in information technology. The present invention also relates to a photoaddressable side chain polymer suitable for producing a component capable of inducing high birefringence by light irradiation to store optically obtainable information or to passively or optically blink.

Photo addressable polymers are known (Polymers as Electrooptical and Photooptical Active Media, V. P. Shibaev (Editor), Springer Verlag, New York 1995). Particularly suitable for this purpose are side chain polymers of the copolymer which are distinguished by possible variations in a very wide range of properties. Their particular feature is that optical properties such as light absorption, emission, reflection, birefringence and scattering can be reversibly changed by light induction. Such polymers have a special branched chain structure, ie, a structure in which side chains capable of absorbing electromagnetic waves are connected through portions of a molecule that act as "spacers" located on a linear backbone. An example of this type is a side chain polymer containing azobenzene groups according to US Pat. No. 5,173,381. Such substrates are characterized by their ability to exhibit birefringence in a particular direction when polarized light is irradiated. The recorded birefringence pattern can be visualized by polarization.

It is also known that locally limited birefringence in which the preferred axis moves with rotation of the polarization direction can be recorded at any position in this polymer layer using polarization (see K. Anderle, R. Birenheide, M. Eich, JH Wendorff, Makromol.Chem., Rapid Commun. 10, 477-483 (1989), J. Stumpe, et al., 20. Freiburger Arbeitstagung Flussigkristalle 1991). This method is slow. In some cases the onset of anisotropic behavior can already be detected after a few seconds of exposure time, but it usually takes several minutes and even hours to achieve its maximum possible. The relationship with the magnitude of the effect is roughly proportional to the time spent. The feature of optical addressing is that the optical axis of the recorded birefringence is perpendicular to the axis of polarization that is recorded. The simple possibility of arbitrarily erasing the recorded information by rotation of the polarization direction of the recording light is based on this property. In this case writing and erasing occur equally fast; These are the same method according to the polarization direction of the used light. This is in contrast to the thermal scavenging method, which heats the layer to a temperature beyond the glass transition of the polymer so that all information is erased at once.

In data display, storage and processing, two fundamentally different paths follow a path that can be named serial and analog. In the analog path all data and information is collected and converted simultaneously. A specific example of this is a photograph using a silver halide film as an analog recording medium. This case involves exposing the polarization to the layer of photoaddressable polymer through the master pattern. Since all image points are developed at the same time, recording (development) time is of little importance in this method. However, processing the list of information by serial means is to convene continuously. For objects with very high information density (e.g., images), potentially many of these image points must be recorded in succession, so that the development time is the sum of the development times of the individual image points. For this reason, high recording speed is important while maintaining sufficient stability of the initial state of the non-recording area as well as the final state of the recording area. In both methods, accurate reproduction of the gradation difference at the luminance (gray level) of the master pattern is also very important. Until now, because boundary conditions are additionally important in addition to the information transfer rate, the problem of high recording speeds by the optical path has not been solved in a technically satisfactory manner. Such boundary conditions include, inter alia, the ability to cancel the degree of stability, eraseability and greyness. There is a fundamental reason for this.

In general, a system in which only a field or vector changes without a mass change reacts very quickly to control the command. When the mass moves, for example in a rearrangement method or chemical reaction, the reaction slows down with size and is also affected by the viscosity of the medium. For example, the switching time of low viscosity nematic rotating cells is in the range of up to m seconds, and the side chain copolymers take several minutes, often many hours, to the maximum attainable birefringence.

If the reversibility of the recorded change is lost, the energy density can be chosen arbitrarily and in limited cases the substrate can be locally compromised. Such materials are described, for example, in G. Kaempf in Kirkothmer, Encyclopaedia of Chemical Technology, 4th ed., 14, 277-338 (1995). However, the various modifications described in this method and in the literature have some disadvantages. Most important of these is that this method involves severe damage to the structure of the substrate and that the holes formed are basically unstable. In addition, there is always a problem of evaporated material that can be deposited anywhere on the device or storage medium, and finally a very high laser energy density of generally above 10 ⁷ mJ / m 2 is required.

Since the preservation of the substrate is a necessary condition for its rewriting at the same time, the light intensity cannot be increased at will, and instead the intensity should be kept below the decomposition limit. Thus, the stability of the material defines the upper limit of the energy density. The minimum amount of energy needed to produce a detectable and stable change in layer was determined by Coles (by polysiloxane) at 4 × 10 ⁶ mJ / m 2 (CB McArdle in Side Chain Liquid Crystal Polymers, Editor. CB McArdle, Blackie Publishers, Glasgow 1989, p. 374]. Estimating the minimum energy for the polymeric substrate is of the same magnitude, and if it is desired to treat the substrate smoothly, the side chain polymer can be slowly recorded (since the minimum energy is already very close to the breaking energy), thus Such polymers are not suitable for cereal storage in real time. This major drawback hindered the technical use of such polymers and the object of the present invention is to alleviate this drawback.

The inventors have surprisingly found that when irradiating a substrate over a large area with a light source suitable for conventional recording, optical anisotropy can be produced to produce a fast addressable storage medium from the original slow photo addressable polymer. Optical anisotropy means that the transmission of light in the plane of the layer changes with direction. This creates direction-dependent refraction, so-called birefringence. When a suitably manufactured substrate is irradiated with light of a moderate intensity for a short time, the birefringence changes rapidly and permanently, i.e. is reduced or completely erased. The degree of residual birefringence can be adjusted according to the light intensity.

Thus, two optical methods that differ from each other in action are included:

In the first manufacturing method, the layer must first be anisotropic birefringent over its area. Birefringence (optical anisotropy) is usually expressed as the difference Δn between the direction dependent refractive index n and the maximum at a particular wavelength.

Any light source for polarization, for example an incandescent lamp in conjunction with a polarizer foil or preferably a laser, is suitable for generating large area anisotropic birefringence. The time required depends only substantially on the power density of the light source, and there is currently no known lower limit for excitation. The upper limit of the power density of the light source is determined by the breaking limit of the material, which depends on the material itself and ranges from 10 ⁷ to 10 ⁸ mW / m 2. The material may be addressed in a structureless manner or, optionally, over a large area, for example, through a mask, with structureless addressing being preferred, but addressing covering the total area of the substrate is particularly preferred. The optical anisotropy Δn of the first method necessary for the purposes of the present invention can be very small and only the essential conditions are still measurable. Preferably, the anisotropic Δn produced in the first process is at least 0.001, in particular at least 0.005, preferably at most 0.95, in particular at most 0.8.

The second optical method relates to the use of the substrate produced in the first optical method, which comprises addressing with very short light while the material is anisotropically birefringent. However, the recording light has an additional amount (it may not be polarized or polarized). It is preferable that the axis of polarization is parallel to the axis of the substrate. The energy density should generally be 10 ³ to 10 ⁷ , preferably 10 ⁵ to 6 × 10 ⁶ mJ / m 2. “Short time” means that the response of light can last for 10 ⁻¹⁵ to 10 ⁻³ , preferably 10 ⁻¹⁰ to 10 ⁻⁵ seconds. The light source should be correspondingly fast, which means that a laser light source is preferred. In this way continuous recording rates of up to 100 MHz, preferably 5 to 50 MHz, are possible. Continuous addressing causes the absorption of photons in the material rapidly, but there is still enough time for the dark reaction.

Erase can occur over a large area, resulting in a nonstructural pattern. The pattern having the structure has a diameter of 10 nm to 20 μm, in particular 10 nm to 1 μm, but is preferably in the direction of minimum extension.

The recorded information is stable, ie the hypotonic birefringence pattern obtained after the light source is turned off can be decoded with the aid of polarization. The change in brightness is proportional to the action of light. The material is capable of gray gradation. The recorded information is reversible, i.e. the information can be erased and then rewritten.

Accordingly, the present invention provides the use of a flat material having an optical anisotropy Δn of 0.001 to 0.95, made from a photoresist polymer for optically available information storage by partially changing the optical anisotropy. Another object of the invention is a method for storing a pattern in a flat material used according to the invention by irradiating with light of an energy density of 10 ³ to 10 ⁷ mJ / m 2 for 10 ⁻³ to 10 ⁻¹⁵ seconds.

The term "optical anisotropy" within the context of the present invention refers to a direction dependent refractive index and maximum of at least 0.001 at a wavelength 30 nm shorter than the point where absorption is still 1% (absorption max = 100%) at the long wavelength edge of the longest wavelength absorption maxima. Means the difference Δn. High anisotropy values as high as possible are preferred because they show good results even at very small layer thicknesses. Preferred Δn values range from 0.05 to 0.95, in particular from 0.1 to 0.8.

The present invention further provides polymers in which optical anisotropy can be prepared by pretreatment, wherein the anisotropy can be varied by exposure of 10 ⁻³ to 10 ⁻¹⁵ seconds.

Suitable polymers for the preparation of photoaddressable substrates are those in which oriented birefringence can be recorded (Polymers as Electrooptical and Photooptical Active Media, VP Shibaev (Editor), Springer Verlag, New York 1995, Natansohn et al., Chem. Mater. 1993, 403-411]. In particular, they are preferably side chain polymers of the copolymer. Preferred examples of such copolymers are described, for example, in DE-OS 43 10 368 and 44 34 966. These are preferably as repeating units Wherein R is hydrogen or methyl, ... represents coupling with other units of the main chain and the side chain is coupled to a carbonyl group) and contains a poly (meth) acrylate backbone that acts as a backbone.

The present invention also provides a polymer having a side chain having the structure described below.

The side chain branching from the main chain may correspond to the following formulas (I) and (II).

-S ¹ -T ¹ -Q ¹ -A

-S ² -T ² -Q ² -M

Where

S ¹ and S ² independently of one another represent an O, S or NR ¹ radical,

R ¹ represents hydrogen or C ₁ -C ₄ alkyl,

T ¹ and T ² independently represent a (CH ₂ ) _n group, which may be optionally interrupted by —O—, —NR ¹ — or —OSiR ¹ ₂ O— and / or substituted by methyl or ethyl There is,

n represents the integer 2, 3 or 4,

Q ¹ and Q ² represent a divalent radical,

A represents a unit capable of absorbing electromagnetic waves,

M represents a polarizable aromatic group containing at least 12 π-electrons.

Especially preferred is Q^OneAnd Q²Z independently of each other^OneAnd Z²or -Z^One-X-Z²Represents-(where Z^OneAnd Z²Are independently of each other -S-, -SO₂, -O-, -COO-, -OCO-, -CONR^One-, -NR^OneCO-, -NR^One-, -N = N-, -CH = CH-, -N = CH-, -CH = N- or-(CH₂)_m-Group (indicates m = 1 or 2),

X is a 5 or 6 membered alicyclic, aromatic or heterocyclic ring, and when Z ¹ represents -COO- or -CONR ^1- , a direct bond or a-(CH = CH) _m -group (m is as described above) ) Is a polymer.

A represents a radical of the monoazo dye absorbing in the wavelength range of 650 to 340 nm.

M represents a linear system saturated with polarized radicals and further polarizable aromatics, at least 12 π-electrons.

Preferred A radicals are of the formula to be.

Where

R ² to R ⁷ are independently of each other hydrogen, hydroxy, halogen, nitro, cyano, C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, CF ₃ , CCl ₃ , CBr ₃ , SO ₂ CF ₃ , C ₁ -C ₆ alkylsulfonyl, phenylsulfonyl, C ₁ -C ₆ alkylaminosulfonyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarbonyl, phenylaminocarbonyl or COOR ¹ .

Preferred M radicals are of the formula to be.

Where

R ⁸ to R ¹³ independently of one another are hydrogen, hydroxy, halogen, nitro, cyano, C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, CF ₃ , CCl ₃ , CBr ₃ , SO ₂ CF ₃ , C ₁ -C ₆ alkylsulfonyl, phenylsulfonyl, C ₁ -C ₆ alkylaminosulfonyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarbonyl, phenylaminocarbonyl or COOR ¹ ,

Y is —COO—, —OCO—, —CONH—, —NHCO—, —O—, —NH—, —N (CH ₃ ) — or a single bond.

Preferred are amorphous polymers, ie polymers which do not form a macroscopically detectable liquid crystalline phase. "Amorphous" means optionally isotropic state. Such polymers do not scatter visible light and contain no double bonds.

These compounds can be prepared by methods known per se to copolymerize mesogen-containing and dye-containing monomers by polymeric reaction or polycondensation. At elevated temperatures, the monomers, i.e. monomers on one side which are mesogenic groups and dye-containing groups on one side, are usually present at elevated temperatures in the presence of a polymerization initiator which supplies conventional radicals such as, for example, azodiisobutyronitrile or benzoyl peroxide At 30 to 130 ° C., preferably 40 to 70 ° C., as much as possible, excluding moisture and air, aromatic hydrocarbons such as toluene or xylene, aromatic halogenated hydrocarbons such as chlorobenzene, ethers such as tetrahydrofuran and dioxane Preference is given to free radical copolymerization in suitable solvents, such as acetone and / or amides such as dimethyl formamide, such as acetone and cyclohexanone. Purification can be carried out by precipitating or dissolving and reprecipitating side chain copolymers produced from a solution thereof, such as methanol.

Whereas groups capable of absorbing electromagnetic waves generally absorb at the wavelength of visible light, the mesogenic groups of the side chain polymers known so far have absorption peaks at substantially shorter wavelengths, preferably at frequencies of about 33,000 cm ⁻¹ , The change in possible birefringence is less than 0.1. The methods described so far for storing information using changes in birefringence have been described as being typically reversible, i.e. the stored information can be erased again by an increase in temperature caused by light or heat, where light The use of may provide the advantage of locally limited erasure possibilities, and this form is often preferred. Of course, the main erase method by supplying energy in the form of heat carries the risk of lack of thermal stability of the written information, which in practice is a disadvantage of the prior art known so far. Many compounds of this type thus have the disadvantage that the birefringence written is not thermally stable, ie the birefringence is weakened at high temperatures, in particular as it approaches the glass transition temperature, and finally disappears completely. Thus, there is a need for an information carrier in which the stability of the written information is as insensitive to heat as possible.

It has been found that good side chain polymers are formed when the side chains are chosen such that their absorption maximum points are constantly off of one another. Information that is very thermally stable in this new polymer can be recorded using light.

The present invention thus has different types of side chains on the backbone acting as a skeleton, both of which can absorb electromagnetic waves (at least in one type, preferably at visible wavelengths), but these different side chains. The absorption maximum points of are directed to polymers which are at least 200 apart, preferably at least 500 and at most 10,000, preferably at most 9,000 cm ⁻¹ .

Preferred polymers according to the invention have covalently bonded side chains of formula (I) and formula (II), branching therefrom onto the main chain serving as the backbone.

<Formula I>

-S ¹ -T ¹ -Q ¹ -A

<Formula II>

-S ² -T ² -Q ² -P

Where

S ¹ and S ² independently of each other represent oxygen, sulfur or NR ¹ ,

R ¹ represents hydrogen or C ₁ -C ₄ alkyl,

T ¹ and T ² independently of one another represent a (CH ₂ ) _n radical, which may be optionally interrupted by —O—, —NR ¹ — or —OSiR ¹ ₂ O— and / or optionally substituted with methyl or ethyl Can be,

n represents the integer 2, 3 or 4,

Q ¹ and Q ² independently represent a divalent radical,

A and P represent units that can absorb electromagnetic waves independently of each other,

Provided that the absorption maximum points of the -Q ¹ -A and -Q ² -P radicals are at least 200, preferably at least 500, and at most 10,000, preferably at most 9000 cm ⁻¹ apart from each other.

One key feature of the present invention is the discovery that the closer the terminal groups -Q ¹ -A and -Q ² -P are to each other, the better the properties of the polymers according to the invention. This applies in particular in terms of electronic structure. The coincidence of the two groups should be high, but not 100%. Exciting a group absorbing at a longer wavelength to the first excited electron ( ¹ S ₀ ) state makes the orbital symmetry of the A and P groups approximately asymmetric.

The function of the T ¹ and T ² radicals is to ensure a constant distance between the side chain ends and the chain acting as the backbone. Thus they are called "spacers".

The Q ¹ and Q ² radicals connect the terminal groups A and P to the spacers T ¹ and T ² , respectively, and T ¹ and T ² also connect to the main chain via the linking element S ¹ or S ² , respectively. A special aspect of the Q ¹ and Q ² groups is their influence on both A and P on one side and T ¹ and T ² on the other. The Q ¹ and Q ² radicals therefore have very particular importance, for example, the similarity of the structure of -Q ¹ -A and -Q ² -P with a relatively similar position of the absorption maximum point, for example the same radicals A and P can be achieved by polarizing significantly differently from each other by different radicals Q ¹ and Q ² .

Preferred radicals Q ¹ and Q ² independently of one another are -S-, -SO ₂ , -O-, -COO-, -OCO-, -CONR ^1- , -NR ¹ CO-, -NR ¹ -,-(CH _{2) m} - (m = 1 or 2), and optionally 1 or 2 containing one N atom (in this case, coupling to the T ¹ and a or T ² and P radical is tongham these N atoms), a bivalent 6 won Ring and Z ¹ -XZ ² groups,

Z ¹ and Z ² independently of one another are -S-, -SO ₂ , -O-, -COO-, -OCO-, -CONR ^1- , -NR ¹ CO-, -NR ^1- , -N = N- , -CH = CH-, -N = CH-, -CH = N- or-(CH ₂ ) _m -group (m = 1 or 2),

X represents a naphthalene radical, a 5 or 6 membered alicyclic, aromatic or heterocyclic ring, a-(CH = CH) _m -group (m = 1 or 2) or a direct bond.

Particularly preferred radicals X include 2,6-naphthylene and 1,4-phenylene and heterocyclic radicals of the formula

When X represents a five-membered ring system, it may be a carbocyclic ring or, preferably, a heteroaromatic system, and may contain up to three heteroatoms, preferably up to a series of S, N and O. Suitable samples are for example thiophene, thiazole, oxazole, triazole, oxadiazole and thiadiazole. Particular preference is given to heterocyclic groups containing two heteroatoms.

When X represents a-(CH = CH) _m -group, the value of m becomes like this.

When X represents a direct bond, for example an oxalic acid derivative, urea derivative or carbamate (selection Z from Z ¹ and Z ² ) is obtained.

Preferred meanings of Z ¹ -XZ ² are -OC ₆ H ₄ -COO-, -OC ₆ H ₄ -CO-NR ^1- , -NR ¹ -C ₆ H ₄ -COO-, -NR ¹ -C ₆ H ₄ a -CO-NR ¹ kind acid amide radicals and benzoic acid ester radicals and -OCO-CH = CH-OCO-, and ^{-NR 1 -CO-CH = CH-} CO-NR 1 kind of a fumaric acid ester and fumaric acid amide radical.

Especially preferably, Q ¹ represents a -Z ¹ -C ₆ H ₄ -N = N- group, and Q ² represents a -Z ¹ -C ₆ H ₄ -CO-NH- group.

The -Q ¹ -A group must have an absorption maximum point in the wavelength range of 15,000 to 28,000 cm ^-1 and the -Q ² -P group must have an absorption maximum point in the wavelength range of 16,000 to 29,000 cm ^-1 . For the purposes of the present invention, A and P, and Q ¹ and Q ² are defined such that a unit absorbing at a longer wavelength is called -Q ¹ -A and a unit absorbing at a shorter wavelength is called -Q ² -P. do.

Preferred A and P radicals are such as mononuclear and polynuclear radicals such as cinnamic acid, biphenyl, stilbene and azo dye radicals, benzoic acid anilides or analogs of the heterocyclic type, preferably monoazo dye radicals.

Particularly preferred A and P radicals correspond to formula (III).

-E-N = N-G

Where

G represents a monovalent aromatic or heterocyclic radical,

E represents a divalent aromatic or heterocyclic radical.

Suitable aromatic radicals for E preferably contain 6 to 14 carbon atoms in the aromatic ring, which ring is C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy, hydroxy, halogen (particularly F, Cl or Br). ), Amino, nitro, trifluoromethyl, cyano, carboxy, COOR (R = C ₁ -C ₆ alkyl, cyclohexyl, benzyl, phenyl), C ₅ -C ₁₂ cycloalkyl, C ₁ -C ₁₂ alkylthio , C ₁ -C ₆ alkylsulfonyl, C ₆ -C ₁₂ arylsulfonyl, aminosulfonyl, C ₁ -C ₆ alkylaminosulfonyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarba Carbonyl, phenylaminocarbonyl, C ₁ -C ₄ alkylamino, di-C ₁ -C ₄ alkylamino, phenylamino, C ₁ -C ₅ acylamino, C ₁ -C ₄ alkylsulfonylamino, mono- or di It may be single or polysubstituted with -C ₁ -C ₄ alkylaminocarbonylamino, C ₁ -C ₄ alkoxycarbonylamino or trifluoromethylsulfonyl.

Suitable heterocyclic radicals for E preferably contain 5 to 14 ring atoms, 1 to 4 of which are heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, and the heterocyclic system is C ₁ -C ₁₂ alkyl , C ₁ -C ₁₂ alkoxy, hydroxy, halogen (especially F, Cl or Br), amino, nitro, trifluoromethyl, cyano, carboxy, COOR (R = C ₁ -C ₆ alkyl, cyclohexyl, benzyl , Phenyl), C ₅ -C ₁₂ cycloalkyl, C ₁ -C ₁₂ alkylthio, C ₁ -C ₆ alkylsulfonyl, C ₆ -C ₁₂ arylsulfonyl, aminosulfonyl, C ₁ -C ₆ alkylaminosul Ponyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarbonyl, phenylaminocarbonyl, C ₁ -C ₄ alkylamino, di-C ₁ -C ₄ alkylamino, phenylamino, C _1- C ₅ acylamino, C ₁ -C ₄ alkylsulfonyl amino, mono- or di -C ₁ -C ₄ alkyl aminocarbonylamino, C ₁ -C ₄ alkoxycarbonylamino or trifluoromethoxy It may be single or multi-substituted with a sulfonyl.

Suitable aromatic radicals for G preferably contain 6 to 14 carbon atoms in the aromatic ring, which ring is C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy, hydroxy, halogen (particularly F, Cl or Br). ), Amino, nitro, trifluoromethyl, cyano, carboxy, COOR (R = C ₁ -C ₆ alkyl, cyclohexyl, benzyl, phenyl), C ₅ -C ₁₂ cycloalkyl, C ₁ -C ₁₂ alkylthio , C ₁ -C ₆ alkylsulfonyl, C ₆ -C ₁₂ arylsulfonyl, aminosulfonyl, C ₁ -C ₆ alkylaminosulfonyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarba Carbonyl, phenylaminocarbonyl, C ₁ -C ₄ alkylamino, di-C ₁ -C ₄ alkylamino, phenylamino, C ₁ -C ₅ acylamino, C ₁ -C ₁₀ arylcarbonylamino, pyridylcarbonyl amino, C ₁ -C ₄ alkylsulfonylamino, C ₆ -C ₁₂ arylsulfonyl, amino, mono- or di -C ₁ -C ₄ alkyl aminocarbonylamino, C ₁ -C ₄ alkoxycarbonyl-amino or tri By Luo as methylsulfonyl may be singly or multiply substituted.

Suitable heterocyclic radicals for G preferably contain 5 to 14 ring atoms, of which 1 to 4 are heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur and the heterocyclic system is C ₁ -C ₁₂ alkyl , C ₁ -C ₁₂ alkoxy, hydroxy, halogen (especially F, Cl or Br), amino, nitro, trifluoromethyl, cyano, carboxy, COOR (R = C ₁ -C ₆ alkyl, cyclohexyl, benzyl , Phenyl), C ₅ -C ₁₂ cycloalkyl, C ₁ -C ₁₂ alkylthio, C ₁ -C ₆ alkylsulfonyl, C ₆ -C ₁₂ arylsulfonyl, aminosulfonyl, C ₁ -C ₆ alkylaminosul Ponyl, phenylaminosulfonyl, aminocarbonyl, C ₁ -C ₆ alkylaminocarbonyl, phenylaminocarbonyl, C ₁ -C ₄ alkylamino, di-C ₁ -C ₄ alkylamino, phenylamino, C _1- C ₅ acylamino, C ₁ -C ₄ alkylsulfonyl amino, mono- or di -C ₁ -C ₄ alkyl aminocarbonylamino, C ₁ -C ₄ alkoxycarbonylamino or trifluoromethoxy It may be single or multi-substituted with a sulfonyl.

When the E or G radicals are polysubstituted, in each case the number of substituents depends on the number of possible substitution positions, the possibility of introducing substituents, and the nature of the substituted system. Aryl and acyl groups may be optionally substituted with nitro, cyano, halogen, C ₁ -C ₄ alkoxy or amino.

Particularly preferred -E-N = N-G radicals contain aromatic radicals or heterocyclic radicals (e.g., E or G are aromatic and heterocyclic groups with other groups) or two aromatic radicals (i.e. both E and G are aromatic).

Particularly preferred -E-N = N-G radicals are azobenzene radicals of formula (IV).

Where

R represents nitro, cyano, benzamido, p-chloro, p-cyano or p-nitrobenzamido or dimethylamino, and rings A and B may be further substituted.

Particularly preferred A and P radicals are of formula (V).

Where

R ² to R ⁶ are independently of each other hydrogen, chlorine, bromine, trifluoromethyl, methoxy, SO ₂ CH ₃ , SO ₂ CF ₃ , SO ₂ NH ₂ , N (CH ₃ ) ₂ , preferably nitro, Cyano or p-chloro, p-cyano or p-nitrobenzamido, provided that at least one of these radicals is not hydrogen,

R ⁷ to R ¹⁰ independently represent hydrogen, chlorine or methyl.

When ring A is polysubstituted, the 2,4- and 3,4-positions are preferred.

Another preferred A and P radical corresponds to formula (VI).

Where

R ² to R ⁶ and R ⁷ to R ¹⁰ have the same meaning as described above,

R ^{2 '} to R ^6' have the meaning of R ² to R ⁶ , but are independent of them.

Another preferred A and P radical corresponds to formula (VII).

Where

K, L and M independently of one another represent N, S or O atoms or optionally -CH ₂ -or -CH = provided that at least one of the members K, L and M is a heteroatom and ring A is saturated or 1 to Contains two double bonds,

R ⁷ to R ¹¹ independently of each other have the meaning given to R ⁷ to R ¹⁰ above.

Ring A preferably represents a thiophene, thiazole, oxazole, triazole, oxadiazole or thiadiazole group.

Preferred -Q ¹ -A and -Q ² -P radicals correspond to formula (VIII) or formula (IX).

Where

R ¹ to R ¹⁰ are as described above.

Preferred groups A and P correspond to formulas (X) and (XI).

Where

R ² represents hydrogen or cyano,

R ^{2 '} represents hydrogen or methyl,

W represents oxygen or NR ¹ ,

R ⁴ represents nitro, cyano, benzamido, p-chloro, p-cyano or p-nitrobenzamido or dimethylamino.

The above formulas are characterized by particular preference in being substituted at the 4-, 2,4- and 3,4-positions of ring A.

Preferred for these preferred A and P groups -S ¹ -T ¹ -Q ¹ -and -S ² -T ² -Q ² -are of the formula -OCH ₂ CH ₂ O-, -OCH ₂ CH ₂ OCH ₂ CH ₂ Corresponds to O- and -OCH ₂ CH ₂ -NR ^1- .

Preferred polymers according to the invention contain only repeating units with side chains of the formulas (I) and (II), preferably those of the formulas (XII) and (XIII).

Wherein R = H or preferably methyl.

Corresponding preferred monomers for making polymers having side chains of formulas (I) and (II) thus correspond to formulas (XIV) and (XV).

The side chains of formulas (I) and (II) are therefore preferably bonded to the (meth) acryloyl group CH ₂ = C (R) -CO- (R = hydrogen or methyl).

Preferably the main chain of the side chain polymers of the present invention is formed from monomers having side chains of formula (I), monomers having side chains of formula (II) and optionally further monomers, where in particular the sum of all monomer units introduced On the basis of the proportion of monomers containing the side chain of formula (I), respectively, 10 to 95 mol%, preferably 20 to 70 mol%, and the proportion of monomers having the side chain of formula (II) is 5 to 90 mol. %, Preferably 30 to 80 mol%, and the proportion of additional monomers is 0 to 50 mol%.

“Additional” repeating units are suitable for all basic accessory blocks that can be chemically introduced into the side chain polymer. They substantially only serve to lower the concentrations of the side chains of the formulas (I) and (II) in the polymer, thus essentially producing a "dilution" effect. In the case of poly (meth) acrylates, the "additional" monomers preferably include ethylenically unsaturated copolymerizable monomers having an α-substituted vinyl group or a β-substituted alkyl group, preferably styrene; Also chlorinated and alkylated or alkenylated styrene, such as on the nucleus, wherein the alkyl group may contain 1 to 4 carbon atoms and the alkenyl group may contain 2 to 4 carbon atoms, such as vinyl toluene, divinyl Benzene, α-methyl styrene, tert-butyl styrene and chloroated styrene; Vinyl esters or carboxylic acids having 2 to 6 carbon atoms, preferably those having 1 to 4 carbon atoms in the vinyl acetate, vinyl pyridine, vinyl naphthalene, vinyl cyclohexane, acrylic acid and methacrylic acid and / or alcohol components Esters (preferably vinyl, allyl and metalyl esters), amides and nitriles thereof, maleic anhydride, maleic half- and diesters and maleic acid half-amides and dia having 1 to 4 carbon atoms in the alcohol component Mid and cyclic imides such as N-methyl maleimide or N-cyclohexyl maleimide, allyl compounds such as allyl benzene and allyl esters such as allyl acetate, phthalic diallyl esters, isophthalic acid diallyl esters, fumaric acid diallyl esters , Allyl carbonate, diallyl carbonate, triallyl phosphate and triallyl It may include the isocyanurate.

Preferred "additional" monomers correspond to formula (XVI).

Where

R ¹² represents an optionally branched C ₁ -C ₆ alkyl radical or a radical containing at least one other acrylic radical.

The polymers according to the invention may also have one or more side chains which meet the definition of formula (I), or one or more side chains which conform to the definition of formula (II), or side chains which correspond to the definitions of both formulas (I) and It may contain several.

The polymer according to the invention preferably has a glass transition temperature Tg of at least 40 ° C. Glass transition temperatures are described, for example, in B. Vollmer, Grundrib der Makromolekularen Chemie, (Foundations of Macromolecular Chemistry), pp. 406-410, Springer-Verlag, Heidelberg, 1962].

The polymers according to the invention are generally measured by gel permeation chromatography (corrected with polystyrene) and have a weight average molecular weight of 3,000 to 2,000,000, preferably 5,000 to 1,500,000.

Structural elements with high anisotropy in shape and high molecular anisotropy are a requirement for high optical anisotropy. The intermolecular interactions of the structural elements of formulas (I) and (II) are controlled by the structure of the polymer such that formation of an ordered liquid crystal state is suppressed and an optically isotropic, transparent non-scattering film can be produced. On the other hand, intermolecular interactions are nevertheless strong enough to produce photochemically induced, cooperative, controlled reorientation of the side chains when irradiated with polarization.

In the optically isotropic amorphous polymer according to the present invention, extremely high values of optical anisotropy can be induced by irradiation of polarized light. The value measured for the difference Δn of the birefringence is 0.05 to 0.8.

The light used is preferably linearly polarized light, the wavelength of which is in the absorption band range of the side chain.

The invention also relates to a polymer which can incorporate birefringence change Δn of at least 0.15, preferably at least 0.2, in particular at least 0.4, using polarized light. The Δn value should be measured as described below in the present invention.

The absorption maximum points λ _max1 and λ _max2 are measured first in each case in two homopolymers. A change in birefringence is generated by irradiating a film of the copolymer to be tested using linearly polarized light having a wavelength of (λ _max1 + λ _max2 ): 2. To do this, the sample is irradiated with polarized light in a direction perpendicular to the surface. The output of the light source should be 1000 mW / cm ² , and if the copolymer is broken under these conditions, the output of the light source is lowered in steps of 100 mW until the copolymer is no longer destroyed by irradiation of light. Irradiation continues until the birefringence no longer changes. The change in birefringence generated is measured at a selected wavelength of [(λ _max1 + λ _max2 ): 2] + 350 ± 50 [nm]. The polarization of the measurement light should form an angle of 45 ° with respect to the polarization direction of the recording light.

The preparation of the side chain monomers and their polymerization can be carried out by methods known from the literature. See, eg, Makromolekuare Chemie 187, 1327-1334 (1984) SU 887 574, Europ. Polym. 18, 561 (1982) and Liq. Cryst. 2, 195 (1987), DD 276 297, DE-OS 28 31 909 and 38 08 430. Polymers according to the invention are generally for example aromatic hydrocarbons such as toluene or xylene, aromatic halogenated hydrocarbons such as chlorobenzene, ethers such as tetrahydrofuran or dioxane, ketones such as acetone or cyclohexanone and / or dimethylformamide In suitable solvents such as, for example, azobis (isobutyronitrile) or benzoyl peroxide, in the presence of a polymerization initiator which supplies free radicals, at elevated temperatures, generally at 30 to 130 ° C., preferably at 40 to 70 ° C. Prepared by free radical copolymerization of monomers excluding water and air. Isolation can be carried out by precipitation with an appropriate agent such as methanol. The product can be purified by reprecipitation with chloroform / methanol and the like.

The present invention therefore also provides a process for the preparation of side chain polymers by copolymerization of the corresponding monomers.

The polymers of the invention are treated in layers of 0.1 to 500 μm, preferably 1 to 30 μm, particularly preferably 2 to 10 μm thick. This layer can be cast, knife coated, immersed or spin coated from solution. These can form a self supporting film. However, it is preferably applied to the support material. This is accomplished by various techniques known per se, and the method is selected depending on whether a thick film or a thin film is desired. Thin films can be produced, for example, by spin coating or knife coating from a solution or melt, and thick layers can be produced by melt compression or extrusion.

External field and / or surface effects can be utilized to produce isotropic films without the need for time consuming and expensive orientation processes. Isotropic films can be applied to substrates by spin coating, dipping, casting or other technically controllable coating methods, inserted between two transparent plates by compression or inflow, and self-supporting by casting or extrusion It can also be produced simply from a film. Such films may also be prepared from liquid crystal polymers containing the described structural elements by quenching, ie by a cooling rate of> 100 K / min, or by rapid evacuation of the solvent.

The present invention therefore also provides films of the polymers described herein (both in self-support and in the form of coatings) and supports coated with these films.

The side chain polymers according to the invention are optically isotropic in the glassy state of the polymer, amorphous, transparent and light scattering and can form self supporting films.

However, preferably, the film is applied to a supporting material such as glass or plastic film. This can be done by various techniques known per se and the method is selected depending on whether a thick film or a thin film is desired. Thin films can be produced, for example, by spin coating or knife coating from solutions or melts, and thicker films can be prepared by filling prefabricated cells or by melt compression or extrusion.

The polymers of the invention can be used in the broadest sense for digital or analog data storage, such as optical signal processing, Fourier transform and superposition or coherent optical correlation techniques. Lateral resolution is limited by the wavelength of the recording light, a pixel size of 0.45 to 3,000 μm is possible, and a pixel size of 0.5 to 30 μm is preferred.

Due to these properties, the polymers of the invention are particularly suitable for the processing of images and for information processing via holograms, which can realize reproduction by illuminating the contrast beam. Similarly, the interference pattern can store two monochromatic coherent light sources with a constant phase relationship. Thus, the three-dimensional hologram image can be stored. The image is read by illuminating the hologram with monochromatic coherent light. The relationship between the electrical vector of light and the associated preferred direction in the storage medium can result in higher storage densities than in pure binary systems. In the case of analog storage, the gray scale values can be adjusted continuously and locally. Information stored in an analog manner can be read with polarized light and can create a positive or negative image depending on the position of the polarizer. In this case, the contrast of the film made by the phase difference between normal and abnormal light can be utilized between the two polarizers, where the plane of the polarizer advantageously forms an angle of 45 ° with respect to the polarization plane of the recording light. Perpendicular or parallel to that of the polarizer. Another possibility is to detect the angle of refraction of the read light caused by the induced birefringence.

Polymers are optical components that can be passively or actively switched, and can be used in particular for holographic optics. Thus, highly photoinduced optical anisotropy can be utilized for the electrical manipulation of light intensity and / or polarization states. Thus, parts having image forming properties comparable to lenses or diffraction gratings can be produced by holographic construction from polymer films.

The polymer layer can be used for serial recording of all forms of light transmission data, especially in the medical field.

The present invention therefore also provides for the use of optically anisotropic substrates as information technology, in particular components and holographic recording materials for storing and processing structural elements and information, preferably images.

In the following examples the percentage values are in parts by weight unless otherwise noted.

<Example 1>

1.1 Pre-exposure

A glass plate of 2 × 2 cm size was spin coated with a solution of a polymer having repeat units of the formula:

To achieve as uniform pre-exposure as possible, the plate is pre-exposed to a commercial light box (Planilux LJ-S, light source: two light tubes connected to foil polarizers (15 watts each)). The transmittance value was measured between two crossed polarizers. 7.6% transmission after 1 hour pre-exposure and 13.7% transmission after 2 hour pre-exposure were obtained.

1.2 Record and measurement arrangement

An array of linearly polarized He-Ne lasers connected to the expansion optics, sample holders, rotary polarizing filters, as well as optical cell power meters connected to Ulbricht spheres are used to measure the recorded birefringence. The recorded sample is arranged with respect to the polarization direction of the He-Ne laser such that the angle with respect to the polarization direction of the recording laser is 45 °. The transmission direction of the polarizing filter is perpendicular to the direction of the sampling He-Ne laser. In this arrangement, the transmission laser power is measured with the recording power on the corresponding sample field. Further measurement of the transmission power at the non-recorded sample sites in the "open" position of the polarizing filter is used for standardization.

1.3 Record

Flat surfaces (flat fields) were recorded using the recording arrangement described above. The polarization direction of the recording laser was perpendicular to the transmission direction of the foil polarizer used for pre-exposure. Appropriate data in the record array is as follows:

Laser source: Ar-ion laser, linearly polarized light.

Single line operation, λ = 514.5 nm

Laser power up to 280 mW in the plane of the image

Laser spot size 7-8 μm

Pixel size (line spacing) 5.4 μm

Scanning length 7.41 mm

Scanning Height 5.82 mm

Scanning Speed (Linear) 0.6 to 23.8 m / s

<Examples 2 to 20>

The polymer having the repeating unit shown below was used in place of the polymer or the like used in Example 1 and the same method as described in Example 1 was used to find the following:

In Tables 1, 2, 3 and 4 the symbols have the following meanings:

R is a substituent corresponding to Formula 2, 3, 4, 5,

λ is the wavelength of the maximum absorption point,

Δn is the birefringence change achieved in the first step,

x is the content of the antenna component in the copolymer,

E is the recording energy, and

ε is the optical density at the recording wavelength 514 nm.

Repeat units

R ¹ R ² R ³ R ' ³ R ⁴ R ⁵ λ Δn x Tg E ε 2 CN C H H CH ₃ Et 490 0.043 50 142 1.3 3.36 3 CN H H H H Me 472 0.029 45 141 1.6 3.19 4 CN H CN H H Me 490 0.077 50 144 1.8 2.5 5 NO ₂ H Cl H H Me 490 0.057 49 129 1.9 1.8 6 NO ₂ H H H H Et 484 0.060 48.5 124 2 1.76 7 NO ₂ H H H H Me 469 0.116 44 136 2.1 3 8 NO ₂ H H H H Et 502 0.022 50 131 2.3 3.4 9 CH ₃ H CN CN H Me 483 0.029 51 130 2.4 3.38 10 CN H H H H Me 436 0.074 58 138 2.7 2.13 11 CN H H H CH ₃ Et 488 0.03 50 134 2.8 3.43 12 OCH ₃ H H H H Me 403 0.048 75 118 3.6 0.24 13 Cl H H H H Me 412 0.042 60 99 3.7 0.52 14 CN H H H H Me 452 0.057 75 133 4.1 1.75 15 Br H H H H Me 416 0.016 52 137 4.2 1.51 16 CH ₃ H H H H Me 408 0.05 40 133 4.3 0.57 17 OCH ₃ H Cl H H Me 414 0.032 50 133 4.3 0.3 18 OCH ₃ H H H H Me 407 0.079 45 128 4.5 0.2 19 OCH ₃ H H H H Me 406 0.041 60 123 4.5 0.24 20 OCH ₃ H H H H Me 410 0.028 28 132 5.7 0.19

<Examples 21 to 30>

The polymer having the repeating unit shown below was used in place of the polymer or the like used in Example 1 and the same method as described in Example 1 was used to find the following:

See Example 2 for the meaning of the values shown in the table:

R ¹ R ² R ³ R ⁴ R ⁵ λ Δn x E ε 21 CN H H Me H 439 0.027 60 1.2 - 22 CN H CN Me H 502 0.038 40 1.4 3.34 23 CN CN H Me H 482 0.032 40 2.3 2.24 24 CN H H Et Me 446 0.023 40 2.3 1.7 25 CF ₃ H H Me H 420 0.041 40 2.4 0.6 26 SO ₂ CF ₃ H H Me H 460 0.096 40 2.5 1.91 27 OCH ₃ H H Me H 407 0.034 40 3.4 0.2 28 CN H H Me H 450 0.029 40 4.5 - 29 CN H H Me H 450 0.024 40 4.8 - 30 OCH ₃ H H Me H 412 0.014 60 6.6 0.18

<Examples 31 and 32>

The homopolymer having the repeating unit shown below was used in place of the polymer or the like used in Example 1 and the same method as described in Example 1 was used to find the following:

See Example 2 for the meaning of the values shown in the table:

R ¹ R ² R ³ R ⁴ λ n x E ε 31 CN Me H - 365 0.055 100 3.5 0.2 32 CN Me Me CH ₂ 365 0.042 100 3.8 0.2

<Examples 33 to 36>

The polymer having the repeating unit shown below was used in place of the polymer or the like used in Example 1 and the same method as described in Example 1 was used to find the following:

See Example 2 for the meaning of the values shown in the table:

R ¹ R ² R ³ λ Δn x E ε 33 CN Et Me 443 0.042 60 1.6 1.1 34 CN Et Me 444 0.039 50 1.8 1.1 35 CN Et Me 446 0.067 40 2.2 0.79 36 CF ₃ Me H 420 0.032 60 2.2 0.4 37 CF ₃ Me H 420 0.022 70 3.3 0.4

<Example 38>

Samples prepared as described in Example 1 were run according to the following test cycles:

38.1 Preliminary Exposure of Sample on Light Box Attached to Polarizing Foil (Exposure Time: 1 Hour)

38.2 Record in a recorder array at various laser powers with the polarization of the recording laser at right angles to the polarization of the preliminary exposure

38.3 Renewal exposure of the sample recorded on the light box connected to the polarizing foil, the transmission direction of the polarizer is the same as in the first preliminary exposure (exposure time: 7-8 hours)

38.4 Recording to the Recorder Array Under the Same Conditions as Above

Permeability of the sample after updated pre-exposure (see FIG. 2).

2: Sample permeability T [%] after renewal preexposure to E [10 ⁶ mJ / m ² ]:

Permeability recorded in the absence of thermal structure: black square

Permeability where there is a thermal structure produced during the recording process: white square

3: Permeability T [%] of the sample after update recording for E [10 ⁶ mJ / m ² ]:

Immediately after recording: white square

Initial state after "Erase exposure": black square (see Figure 3)

Final result:

The recorded pattern can be erased completely by updating preliminary exposure where no thermal structure is produced. However, the thermally recorded structure remains after erasure exposure and sample transmission is scattered and reduced in corresponding places.

The behavior of the sample on the update record corresponds to the original record test shown in FIG. 4 (see FIG. 4).

4: Normalized sample permeability T [%] for recording energy E [10 ⁶ mJ / m ² ]

After primary: black square

After secondary record: white square

<Example 39>

Two samples prepared as in Example 1, with repeating units of the formula: were preexposed as in Example 1; More particularly, one sample was pre-exposed to 49% permeability and the other to 61% permeability. A further procedure was followed as in Example 1, and a decrease in permeability [%] for increasing recording energy E [10 ⁶ mJ / m ² ] was obtained as shown in FIG. 5 (see FIG. 5).

Measured from “49% Permeability” recording test: black square

Measured from "61% Permeability" recording test: white square

Example 40 Preparation of Polymer

1.1 Preparation of Monomer

1.1.1 From Methacrylic Chloride

100 g of N-methyl-N- (2-hydroxymethyl) -aniline was dissolved in 100 ml of chloroform. 182.6 g of triethylamine and 137.2 g of methacryl chloride were slowly added dropwise with stirring at 40 ° C., and the mixture was stirred at 40 ° C. overnight. 500 ml of chloroform was then added to the reaction solution, and the mixture was shaken five times with 200 ml of water each time. The organic phase was dried over anhydrous magnesium sulfate, copper chloride (I) was added, the solvent was distilled off and the organic phase was distilled off under high vacuum. Methacrylic esters of hydroxyethylaniline were obtained as water clear liquids at 127-130 ° C./55 millibars. Yield was 49.5 g.

1.1.2 From Methacrylic Acid

To 100 ml of N-methyl-N- (2-hydroxyethyl) -aniline, 265 ml of methacrylic acid and 26.5 g of hydroquinone solution in 398 ml of chloroform was added dropwise with stirring 50 ml of concentrated sulfuric acid at room temperature. . The mixture was left to stand overnight before it was heated and the water from the reaction was removed by azeotropic distillation. After cooling, the pH was brought to 7-8 with concentrated aqueous sodium carbonate solution and shaken with ether to extract the product from this solution. The procedure was continued as described above to yield 56 g.

1.1.3 Monomer with Terminal Group A

At 0-5 ° C., diazotize 7.15 g of 2,4-dicyanoaniline using 24 g nitrosilsulfate in a solution of 100 ml glacial acetic acid, 20 ml phosphoric acid and 7.5 ml sulfuric acid, followed by 1 Stir for hours. The reaction mixture was added to a solution of 15.3 g N-methyl-N- (2-methacryloyloxyethyl) -aniline and 1.5 g urea in 60 ml glacial acetic acid while maintaining the temperature at 10 ° C. After briefly stirring, the pH of the reaction mixture was adjusted to 3 with sodium carbonate solution, the precipitate was suction filtered off, washed with water and dried. 14.4 g of a red solid were obtained, which was used next without further purification.

1.1.4 Monomer with Terminal Group P

27.6 g of 4-amino-2 ', 4'-dicyanoazobenzene in 500 ml of dioxane are added to a solution of 33 g of 4- (2-methacryloyloxy) -ethoxybenzoic acid chloride in 100 ml of dioxane, The mixture was stirred for 2 hours and then the solution was poured into 2 l of water to precipitate the product. The precipitate was suction filtered off, dried and purified by recrystallization twice from dioxane. The obtained product was 30.4 g of yellow red crystals with a melting point of 215-217 ° C.

1.2 Preparation of Copolymer

2.7 g of monomer of 1.1.3 and 5.19 g of monomer of 1.1.4 were polymerized using 0.39 g of azobis (isobutyronitrile) as a polymerization initiator at 75 ° C. in 75 ml of DMF under argon as a protective gas. After 24 hours, the reaction solution was filtered, the DMF was distilled off, and the residue was boiled with methanol to remove unreacted monomer, and the product was finally dried at 120 ° C. under high vacuum. 7.18 g of an amorphous copolymer having an optical transition temperature of 144 ° C. (optical properties mentioned in Example 42.5) were obtained.

The preparation of another polymer can be made by a similar method.

<Example 41> Variation of the interval between the absorption maximum points

Preparation of measurement samples: A glass plate of 1.1 mm thickness in a 2 × 2 cm size was placed in a spin coater (model Suss RC 5) and coated with anhydrous tetrahydrofuran at 2000 rpm. This layer was 0.9 μm thick, transparent and amorphous. Between crossed polarizers, the surface appeared uniformly dark in daylight. No traces of the polarization site were observed.

A small measuring glass plate was exposed to an Ar ion laser at an output of 250 mW / cm ² at a wavelength of 514 nm to cause birefringence. The maximum birefringence Δn achievable in the polymer layer was measured in two steps:

The maximum induced path difference Δλ to brighten between crossed polarizers is calculated by first measuring with an Ehringhaus compensator. Quantitative measurements are performed by compensation of the brightening. This is done by rotating the quartz crystal located in the path of light, which rotation varies the optical path length and thus the path difference. This time, measure the path difference where the light is completely compensated. Measurements should be made with light at wavelengths outside the absorption range of the compound to avoid resonance effects. In general, a He-Ne laser with an emission wavelength of 633 nm is sufficient, and for long wavelength absorption, a diode laser with a wavelength of 820 nm is used for the measurement. The selected wavelength used is shown in the column starting with "λ" in the table below.

In the second step, the layer thickness of the polymer is measured with a mechanical layer thickness measuring instrument (Alphastep 200, manufactured by Tencor Instruments).

The change Δn of the birefringence is calculated from the ratio of the path difference Δλ and the layer thickness d.

The absorption maximum point is calculated by examining the UV / Vis absorption spectrum. In extreme mixtures, only one peak may be evaluated. In this case the unreadable value should be replaced with the value obtained from the corresponding 1: 1-copolymer.

The methods taken in the examples below for the preparation of the compounds and the determination of the data are similar.

When T ¹ = T ² , Q ¹ ≠ Q ² , A ≠ P, the following results are obtained:

<Formula 2>

Example V _A V _P ΔV _PA Δn n m mW / cm ² λ (nm) R ¹ = H; R ² = CN; R ³ = CN; R ⁴ = CN 41.1 20,900 25,300 2,600 0.110 70 30 250 820 R ¹ = CN; R ² = CN; R ³ = H; R ⁴ = CN 41.2 20,300 27,100 6,800 0.183 60 40 60 633 41.3 20,400 26,700 6,300 0.136 40 60 60 633 R ¹ = H; R ² = NO ₂ ; R ³ = H; R ⁴ = CN 41.4 21,400 27,000 5,600 0.176 40 60 60 633 R ¹ = NO ₂ ; R ² = NO ₂ ; R ³ = CN; R ⁴ = CN 41.5 19,300 25,600 6,300 0.190 70 30 250 820 R ¹ = NO ₂ ; R ² = NO ₂ ; R ³ = H; R ⁴ = NO ₂ 41.6 18,000 26,700 8,700 0.106 70 30 250 820

<Formula 3>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) R ¹ = R ² = H 41.7 19,400 27,900 8,300 0.197 50 50 250 820 R ¹ = H; R ² = CN 41.8 20,000 25,400 5,400 0.287 70 30 250 820 R ¹ = CN; R ² = CN 41.9 19,000 25,900 6,900 0.295 60 40 250 820 R ¹ = CN; R ² = H 41.10 19,000 27,400 8,200 0.318 40 60 250 820

<Formula 4>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) 41.11 19,200 27,800 8,600 0.148 50 50 250 820

<Formula 5>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) 41.12 20,700 26,000 5,300 0.120 50 50 250 820

<Formula 6>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) 41.13 18,900 23,400 4,500 0.250 50 50 250 820

<Example 42> T ¹ = T ² ; Q ¹ ≠ Q ² , A = P

<Formula 7>

Copolymers of formula (7) were prepared in analogy to Example 1, samples were prepared and measured according to Example 2. The birefringence change Δn when recorded at 488 nm was obtained as follows:

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) 42.1 25,000 28,000 3,000 0.232 50 50 250 633

<Formula 8>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) R ¹ = R ² = R ³ = R ⁴ = CN 42.2 20,400 25,800 5,400 0.175 90 10 120 633 42.3 20,400 25,400 5,000 0.231 80 20 60 633 42.4 20,400 25,300 4,900 0.414 70 30 60 633 42.5 20,400 25,000 4,600 0.158 60 40 120 633 R ¹ = R ³ = H; R ² = R ⁴ = NO ₂ 42.6 19,200 26,700 7,500 0.171 70 30 250 820 42.7 19,800 25,600 5,800 0.145 50 50 250 820 42.8 21,300 25,000 2,700 0.116 30 30 250 820

<Example 43> T ¹ ≠ T ² ; Q ¹ = Q ² , A = P:

A copolymer of the following composition was prepared similar to Example 1.

<Formula 9>

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) R = CH ₃ 43.1 27,000 27,400 400 0.103 60 40 200 633 R = H 43.2 27,600 28,300 500 0.104 60 40 200 633

Example 44 T ¹ = T ² ; Q ¹ = Q ² , A ≠ P

Example V _A V _P ΔV _PA Δn m n mW / cm ² λ (nm) 44.1 21,600 23,400 1,800 0.211 50 50 60 633

Example 45 Thermal Stability

A 2 x 2 cm sized glass plate was coated as described in Example 1 using the polymer according to Example 3.3 and 11 fields (flat field) such that a series of incremental transmissions between about 0 and 82% were formed at approximately equal intervals. Recorded. The transmittance is measured immediately after recording, which defines the initial state. This specimen was placed in the cow for 2 months at room temperature without any other protective measures. Then in each case another sample of the glass plate was stored for 24 hours in a drying cabinet at 60 ° C., 80 ° C. and 120 ° C. and then the transmittance was measured again. Thus, the values of four groups were obtained and compared with the initial state. The values for transmittance are shown in Table 1 below.

Initial state 2 months / 20 ℃ 24 hours / 60 ℃ 24 hours / 80 ℃ 24 hours / 120 ℃ 82 75.4 68.9 83.6 72.2 73.8 67.2 65.6 75.4 68.9 65.6 60.7 59.0 64.0 54.1 50.8 45.9 52.5 55.8 49.2 54.1 45.9 52.5 55.8 44.3 19.7 24.6 29.5 37.7 19.7 32.8 21.3 24.6 29.5 16.4 19.7 14.8 14.8 26.2 16.4 9.8 9.8 13.1 16.4 11.5 6.6 6.6 11.5 11.5 9.8 0 0 6.6 8.2 4.9

The freshly prepared samples at room temperature are shown in the first column, and the second column repeats the same measurements after 2 months of storage. The other columns correspond to those measured after storage at the temperatures given in column 1. Drawing the values in columns 2 through 5 over the values in column 1 yields a straight line of slope 1. Thus the gray phase does not change under the action of increased temperature.

Claims (14)

Use of a flat material made from a photo addressable polymer and having an optical anisotropy Δn of 0.001 to 0.95 for partially selectively changing optical anisotropy to store optically available information. 2. Use according to claim 1 as a holographic recording material. A method for storing a pattern in a flat material used according to claim 1 by irradiating light at an energy density of 10 ³ to 10 ⁷ mJ / m ² for a duration of 10 ⁻³ to 10 ⁻¹⁵ seconds. Optically anisotropy can be produced by pretreatment, and the anisotropy can be changed by exposure for 10 ^-3 to 10 ^-15 seconds. The method according to claim 4, having various types of side chains on the main chain serving as a skeleton, these two types of chains being capable of absorbing electromagnetic waves (at least one of which is preferably a wavelength of visible light), The separation of absorption maxima is at least 200 cm ⁻¹ and at most 10,000 cm ⁻¹ . A polymer according to claim 5 having side chains of formula (I) and (II). <Formula I> -S ¹ -T ¹ -Q ¹ -A <Formula II> -S ² -T ² -Q ² -P Where S ¹ and S ² independently of each other represent oxygen, sulfur or NR ¹ , R ¹ represents hydrogen or C ₁ -C ₄ alkyl, T ¹ and T ² independently of one another represent a (CH ₂ ) n radical, which may optionally be interrupted by —O—, —NR ¹ — or —OSiR ¹ ₂ O— and / or be substituted with methyl or ethyl Can, n represents the integer 2, 3 or 4, Q ¹ and Q ² independently represent a divalent radical, A and P represent units that can absorb electromagnetic waves independently of each other. The polymer according to any one of claims 4 to 6, wherein A and P correspond to formulas (X) and (XI). <Formula X> <Formula XI> Where R ² represents hydrogen or cyano, R ^{2 '} represents hydrogen or methyl, W represents oxygen or NR ¹ , R ⁴ represents nitro, cyano, benzamido, p-chloro, p-cyano or p-nitrobenzamido or dimethylamino. The group according to any one of claims 4 to 7, wherein -S ¹ -T ¹ -Q ¹ -and -S ² -T ² -Q ² -groups are represented by the formula -OCH ₂ CH ₂ O-, -OCH ₂ CH ₂ Polymers corresponding to OCH ₂ CH ₂ O- and -OCH ₂ CH ₂ -NR ^1- . The polymer according to any one of claims 4 to 8, wherein the main chain is poly (meth) acryloyl. 10. The polymer of claim 4, wherein a birefringent change Δn greater than 0.15 can be recorded by polarization. 11. Chemical formula And A process for producing a polymer according to any one of claims 4 to 10 by copolymerizing monomers of and optionally further monomers with one another. Films made from the polymers according to claim 4. A support coated with a film according to claim 12. Use of the polymer according to claims 4 to 10 for the manufacture of optical structural elements.