JP6492023B2 - Organic nonlinear optical dye, nonlinear optical material, nonlinear optical film and optical element - Google Patents

Description

  The present invention relates to an organic nonlinear optical dye. The present invention also relates to a nonlinear optical material using an organic nonlinear optical dye. The present invention also relates to a nonlinear optical film and an optical element using a nonlinear optical material.

  In the fields of optical information processing, optical communication, etc., it is required to increase the capacity of information and further increase the speed of communication. In recent years, attention has been paid to the use of optical elements utilizing the electro-optic effect (non-linear optical effect) of a compound having nonlinear optical activity (compound exhibiting nonlinear optical response). When a compound having nonlinear optical activity is applied with a strong photoelectric field, the polarization response is not proportional to the strength of the electric field, and the polarization is proportional to the square of the electric field of the light, the third power, or more. Indicates a response. As compounds having nonlinear optical activity, for example, compounds that generate second harmonics and compounds that exhibit the Pockels effect, which is the first-order electro-optic effect, are known.

  A compound having non-linear optical activity exhibits a non-linear optical effect by being arranged in a state lacking an inversion symmetry center. Therefore, when a compound having nonlinear optical activity is used for an optical element, this compound is used in a certain orientation state. In order to create this orientation state, a compound having nonlinear optical activity is mixed with a polymer binder, the mixture is heated to a temperature near its glass transition temperature, and a high voltage is applied, whereby the compound having nonlinear optical activity The dipoles are oriented, and then cooled to solidify the polymer binder to fix the orientation state (so-called poling treatment).

Conventionally, inorganic compounds such as lithium niobate and potassium hydrogen phosphate have been widely used and put into practical use as compounds having nonlinear optical activity. However, in recent years, organic nonlinear optical dyes that have higher nonlinear optical effects than inorganic compounds and have advantages in response speed, photodamage threshold, molecular design freedom, mass productivity, etc. Many reports have been made.
For example, Patent Document 1 discloses a tricyanopyrroline-based electron acceptor unit having a specific structure in which a cyano group and a dicyanomethylidene group are bonded to a ring-constituting carbon atom of a pyrroline ring, and a specific bonded to this electron acceptor unit. It is described that an organic nonlinear optical dye having an electron donor unit having a structure has excellent electro-optical performance and thermal stability.
Patent Document 2 discloses a tricyanopyrroline electron acceptor unit having a specific structure in which a cyano group and a dicyanomethylidene group are bonded to a ring-constituting carbon atom of a pyrroline ring, and an azo group for the electron acceptor unit. It is described that an organic nonlinear optical dye having an electron donor unit having a specific structure bonded with a conjugated chain having a specific structure containing a group is excellent in electro-optical performance, heat resistance and light resistance.

US Pat. No. 7,307,173 Japanese Patent No. 5826206

In order to be a practical organic nonlinear optical dye, in addition to excellent nonlinear optical activity, the stability of the dye itself is an important factor. That is, in practical use of an optical element (such as a light modulation element) using an organic nonlinear optical dye, it is necessary to ensure long-term reliability of the element.
In order to increase the long-term reliability of an optical element to a practically sufficient level in consideration of diversification of the use environment of the optical element (general versatility), the present inventors have proposed an organic nonlinear optical dye used in the element. Is not only heat resistance and light resistance as described in the above-mentioned patent document, but also has a high degree of ability to continuously express desired nonlinear optical activity without being decomposed for a long time even in a severe environment of high temperature and high humidity. It came to the idea that a high heat resistance was required. Based on this idea, as a result of investigations on the existing organic nonlinear optical dyes and the like by the present inventors, conventional organic nonlinear optical dyes including the organic nonlinear optical dyes described in the respective patent documents described above are not sufficiently heat-resistant. In addition, it has been clarified that it is not possible to realize both the wet heat resistance and the light resistance at a sufficiently high level to a level required for practical use.

  Accordingly, the present invention provides an organic nonlinear optical dye that is excellent in nonlinear optical activity and realizes both light resistance and wet heat resistance at a higher level, a nonlinear optical material using this dye, a nonlinear optical film, and an optical element. This is the issue.

As a result of intensive studies in view of the above problems, the present inventors have obtained a tricyanopyrroline-based electron acceptor unit having a specific structure in which an unsubstituted branched alkyl group is introduced into the ring nitrogen atom of the pyrroline ring in the molecule, An organic nonlinear optical dye having an electron donor unit having an unsubstituted di-branched alkylamino group at the terminal bonded to the electron acceptor unit with a conjugated chain having a specific structure is excellent in nonlinear optical activity, high temperature and high It has been found that, even when exposed to a humid environment for a long period of time, decomposition or the like hardly occurs even when irradiated with ultraviolet rays, and desired optical characteristics can be stably expressed over a long period of time.
The present invention has been further studied based on these findings and has been completed.

一般式（II）中、Ｒ^１及びＲ^２は無置換の分岐アルキル基を示し、Ｒ^３は無置換の分岐アルキル基を有する基を示す。Ｒ ^４ 〜Ｒ ^７ は水素原子又はアルキル基を示す。
〔２〕
上記Ｒ^４〜Ｒ^７が水素原子である、〔１〕に記載の有機非線形光学色素。
〔３〕
〔１〕または〔２〕に記載の有機非線形光学色素と、ガラス転移温度が１００℃以上のポリマーとを含む非線形光学材料。
〔４〕
上記非線形光学材料中において、上記有機非線形光学色素と上記のガラス転移温度が１００℃以上のポリマーの含有量の合計に占める上記有機非線形光学色素の含有量の割合が１０〜５０質量％である、〔３〕に記載の非線形光学材料。
〔５〕
〔３〕又は〔４〕に記載の非線形光学材料を用いた非線形光学膜。
〔６〕
〔３〕又は〔４〕に記載の非線形光学材料を用いた光学素子。
〔７〕
上記光学素子が光変調素子である、〔６〕に記載の光学素子。 The above-described problems of the present invention have been solved by the following means.
[1]
An organic nonlinear optical dye represented by the following general formula (II) .

In the general formula (II) , R ¹ and R ² represent an unsubstituted branched alkyl group, and R ³ represents a group having an unsubstituted branched alkyl group. R ^{4 to} R ⁷ represent a hydrogen atom or an alkyl group.
[ 2 ]
The organic nonlinear optical dye according to [ 1 ], wherein R ^{4 to} R ⁷ are hydrogen atoms.
[ 3 ]
A nonlinear optical material comprising the organic nonlinear optical dye according to [1] or [2] and a polymer having a glass transition temperature of 100 ° C. or higher.
[ 4 ]
In the nonlinear optical material, the content ratio of the organic nonlinear optical dye in the total content of the organic nonlinear optical dye and the polymer having a glass transition temperature of 100 ° C. or higher is 10 to 50% by mass. [ 3 ] The nonlinear optical material according to [ 3 ].
[ 5 ]
The nonlinear optical film using the nonlinear optical material as described in [ 3 ] or [ 4 ].
[ 6 ]
The optical element using the nonlinear optical material as described in [ 3 ] or [ 4 ].
[ 7 ]
The optical element according to [ 6 ], wherein the optical element is a light modulation element.

  In the present specification, when there are a plurality of substituents, linking groups, and the like (hereinafter referred to as substituents) indicated by specific symbols, or when a plurality of substituents are specified simultaneously or alternatively, It means that a substituent etc. may mutually be same or different. The same applies to the definition of the number of substituents and the like. Further, when there are repetitions of a plurality of partial structures represented by the same indication in the formula, each partial structure or repeating unit may be the same or different. Further, unless otherwise specified, when a plurality of substituents and the like are adjacent (particularly adjacent), they may be connected to each other or condensed to form a ring.

  In this specification, about the display of a compound, it uses in the meaning containing its salt and its ion besides the compound itself. In addition, it means that a part of the structure is changed as long as the desired effect is achieved.

  In the present specification, a substituent that does not clearly indicate substitution or non-substitution (the same applies to a linking group) means that the group may further have a substituent as long as the intended effect is not impaired. . This is also synonymous for compounds that do not specify substitution / non-substitution.

  In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  The organic nonlinear optical dye, nonlinear optical material, and nonlinear optical film of the present invention are excellent in nonlinear optical activity, and can achieve both of light resistance and wet heat resistance at a high level. The optical element of the present invention uses the organic nonlinear optical dye or nonlinear optical material of the present invention, and is excellent in long-term reliability.

  The preferred embodiments of the organic nonlinear optical dye, nonlinear optical material, nonlinear optical film and optical element of the present invention will be described in order.

[Organic nonlinear optical dye]
The organic nonlinear optical dye of the present invention is represented by the following general formula (I).

In general formula (I), R ¹ and R ² represent an unsubstituted branched alkyl group. The unsubstituted branched alkyl group that can be adopted as R ¹ and R ² has preferably 3 to 25 carbon atoms, more preferably 4 to 20 carbon atoms, and still more preferably 5 to 15 carbon atoms, including the branched chain structure. 6-10 are particularly preferred. In the unsubstituted branched alkyl group that can be adopted as R ¹ and R ² , the number of branches (the number of branching sites) is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.
In the unsubstituted branched alkyl group that can be adopted as R ¹ and R ² , when the number of branches is 1, it is preferably represented by the following general formula (I-1).

In the above general formula (I-1), * represents a binding site.
k, m and n are preferably integers of 0 to 10, more preferably 0 to 6, and even more preferably 0 to 3.
The total of k, m, and n is preferably an integer of 1 to 20, more preferably an integer of 2 to 15, more preferably an integer of 2 to 10, and further preferably an integer of 3 to 7.
Examples of preferred combinations of k, m and n are shown in Table 1 below. Of the combination examples shown in Table 1 below, combination example 1, combination example 3 or combination example 4 is preferable, and combination example 1 is particularly preferable.

In the general formula (I), R ¹ and R ² may be the same or different from each other, and are preferably the same from the viewpoint of orientation.

R ³ represents a group having an unsubstituted branched alkyl group. That is, R ³ may be an unsubstituted branched alkyl group or a group having an unsubstituted branched alkyl group as a substituent.
The preferred form of the unsubstituted branched alkyl group that R ³ has is the same as the preferred form of the unsubstituted branched alkyl group that can be employed as R ¹ and R ² .

When R ³ is a group having an unsubstituted branched alkyl group as a substituent, the molecular weight of R ³ is preferably from 100 to 800, more preferably from 120 to 500.
When R ³ is a group having an unsubstituted branched alkyl group as a substituent, it is preferably represented by the following general formula (I-2).

In the general formula (I-2), p is preferably an integer of 1 to 10, more preferably an integer of 1 to 8, and still more preferably an integer of 1 to 5.
L ¹ represents —O—C (═O) —, —C (═O) —O—, —O—Si (CH ₃ ) ₂ —, —Si (CH ₃ ) ₂ —O—, —NH—C ( = O)-or -C (= O) -NH-.

In the general formula (I), L represents a divalent linking group composed of a conjugated chain containing -N = N- (azo group) in the chain. L is preferably a divalent linking group formed by combining divalent groups selected from -N = N-, -CH = CH-, -C≡C-, an arylene group, and a heteroarylene group (provided that- N = N-), -N = N-, -CH = CH-, an arylene group, and a divalent linking group formed by combining divalent groups selected from a heteroarylene group. Preferred (provided that at least one -N = N- is included). The arylene group that can constitute L is preferably a phenylene group. The heteroarylene group that can constitute L is preferably a 5-membered or 6-membered monocyclic group.
L preferably has a molecular weight of 200 to 1,000, and more preferably 300 to 600.

  The organic nonlinear optical dye represented by the general formula (I) is more preferably represented by the following general formula (II).

In the general formula ^(II), R 1 ~R ³ are each the same meaning as ^R 1 to R ³ in the general formula (I), and preferred forms are also the same.

R ^{4 to} R ⁷ are preferably a hydrogen atom or an alkyl group. This alkyl group is preferably a group represented by the above general formula (I-1) or (I-2), and is described in the group represented by the above general formula (I-1) or (I-2). The preferred form can be preferably employed as the alkyl group of R ^{4 to} R ⁷ .
R ^{4 to} R ⁷ are preferably all hydrogen atoms, or three of R ^{4 to} R ⁷ are preferably hydrogen atoms and the remaining one is preferably the above alkyl group. More preferably, all of R ^{4 to} R ⁷ are hydrogen atoms.

  The organic nonlinear optical dye of the present invention preferably has a molecular weight of 500 to 2000, more preferably 600 to 1000.

  Specific preferred examples of the organic nonlinear optical dye of the present invention are shown below, but the present invention is not limited to these dyes.

[Nonlinear optical materials]
The nonlinear optical material of the present invention contains the above-described organic nonlinear optical dye of the present invention and a polymer having a glass transition temperature (Tg) of 100 ° C. or higher (hereinafter simply referred to as “high Tg polymer”). The high Tg polymer functions as a binder. The nonlinear optical material of the present invention can contain one or more organic nonlinear optical dyes of the present invention. The nonlinear optical material of the present invention can contain one or more high Tg polymers.
The nonlinear optical material of the present invention is preferably in the form of a composition. That is, the nonlinear optical material of the present invention is preferably in a form in which each component is mixed homogeneously. The nonlinear optical material of the present invention may be a liquid composition obtained by dissolving each component in an organic solvent described later, or may have a specific shape without containing a solvent. In general, the nonlinear optical material of the present invention is applied to a substrate or the like in the form of a liquid composition, and then the solvent is removed by drying to be used for the intended use. As described later, by using the nonlinear optical material of the present invention, a nonlinear optical film or an optical element described later can be manufactured.
In the nonlinear optical material of the present invention, the content of the organic nonlinear optical dye in the total content of the organic nonlinear optical dye and the high Tg polymer is preferably 5 to 50% by mass, and more preferably 6 to 30% by mass.

<Polymer with glass transition temperature of 100 ° C. or higher>
The high Tg polymer contained in the nonlinear optical material of the present invention is not particularly limited as long as Tg is 100 ° C. or higher. For example, polycarbonate, poly (meth) acrylate (preferably poly (meth) methyl acrylate) ), Amorphous fluoropolymer, polyimide and the like can be widely used. The nonlinear optical material of the present invention may contain two or more kinds of polymers.
In this specification, Tg is measured using a differential scanning calorimeter (DSC). More specifically, at the intersection of the slope of the rising end of the endothermic process accompanying the glass transition and the baseline when measured at a rate of 10 ° C./min from room temperature using a differential scanning calorimeter (DSC). Let the corresponding temperature be Tg.
The high Tg polymer preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 10,000 to 50,000. The weight average molecular weight is, for example, using a high-speed GPC apparatus (manufactured by Toyo Soda Co., Ltd., HLC-802A), using a 0.5% by mass THF solution as a sample solution, and using one TSKgel HZM-M column. 200 μL of sample can be injected, eluted with the above THF solution, and measured at 25 ° C. with a refractive index detector or a UV detector (detection wavelength 254 nm). The measurement result is a molecular weight in terms of polyethylene glycol.
The Tg of the high Tg polymer is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. If the Tg of the high Tg polymer is too high, the Tg of the whole material may be too high depending on the blending amount of the polymer, and the temperature of the poling treatment described later may not be kept low. Therefore, the Tg of the high Tg polymer is usually 250 ° C. or lower, and preferably 200 ° C. or lower.

In the nonlinear optical material of the present invention, the ratio of the content of the high Tg polymer to the total content of the organic nonlinear optical dye and the high Tg polymer is preferably 50 to 95% by mass, and preferably 70 to 94% by mass. It is more preferable.
When the nonlinear optical material of the present invention contains the above-described high Tg polymer, the orientation state of the organic nonlinear optical dye after the poling treatment can be kept stable as compared with the case where no high Tg polymer is contained.

<Other ingredients>
The nonlinear optical material of the present invention may contain components other than the organic nonlinear optical dye and other than the high Tg polymer. For example, the nonlinear optical material of the present invention may contain a curing agent, a curing accelerator, a polymerization initiator, an antioxidant, an ultraviolet absorber, an organic solvent, and the like.

  The nonlinear optical material of the present invention preferably has a Tg of 100 ° C. or higher, more preferably 130 ° C. or higher, as a whole. The higher the Tg of the nonlinear optical material, the higher the alignment fixability after the poling process described later. The Tg of the nonlinear optical material of the present invention is usually 200 ° C. or lower.

[Nonlinear optical film]
The nonlinear optical film of the present invention is formed using the nonlinear optical material of the present invention. More specifically, it is a film formed by forming a film using the nonlinear optical material of the present invention and orienting the nonlinear optical dye of the present invention by subjecting it to a poling process described later. There is no restriction | limiting in particular in the film-forming method, A normal method can be employ | adopted. For example, the nonlinear optical material (composition) of the present invention obtained by dissolving the nonlinear optical dye of the present invention, a high Tg polymer, and, if necessary, other components in an organic solvent, spin coating, blade coating, A wet coating method in which a film is formed by coating on a substrate using a dip coating method, an ink jet method, a spray method, or the like, and drying can be employed.

  The organic solvent is not limited as long as it can dissolve the components of the nonlinear optical material of the present invention, and preferably has a boiling point in the range of 80 to 200 ° C. If an organic solvent having a boiling point of less than 80 ° C. is used, solvent volatilization may occur during storage of the coating solution, and the viscosity of the coating solution may increase, or condensation may occur due to the solvent's volatilization rate being too fast during coating. On the other hand, when an organic solvent having a boiling point exceeding 200 ° C. is used, it is difficult to remove the solvent after coating, and the remaining organic solvent acts as a plasticizer for the high Tg polymer, so that the nonlinear optical performance of the film tends to deteriorate.

  Examples of preferred organic solvents include diethylene glycol dimethyl ether, cyclopentanone, cyclohexanone, cyclohexanol, toluene, chlorobenzene, xylene, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, 2,2,3,3 -Tetrafluoro-1-propanol, 1,2-dichloroethane, 1,2-dichloropropane, 1,3-dichloropropane, 1,2,3-trichloropropane and the like. These organic solvents may be used alone or in combination. In addition, a mixed solvent obtained by adding an organic solvent such as tetrahydrofuran, methyl ethyl ketone, isopropanol, or chloroform having a boiling point of less than 80 ° C. to these preferable organic solvents may be used.

<Polling processing>
In the nonlinear optical film of the present invention, an organic nonlinear optical dye is oriented in the film, thereby exhibiting nonlinear optical activity. The alignment of the organic nonlinear optical dye can be performed by a known poling process such as an optical poling method, an optically assisted electric field poling method, and an electric field poling method. Of these, the electric field poling method is particularly preferable in terms of the simplicity of the apparatus and the high degree of orientation obtained.

  The electric field poling method is largely classified into a contact poling method in which a nonlinear optical material is sandwiched between a pair of electrodes and an electric field is applied, and a corona poling method in which a corona discharge is applied to the surface of the nonlinear optical material on the substrate electrode and a charging electric field is applied. Separated. The electric field poling method is an alignment method in which the organic nonlinear optical dye is aligned (polled) in the direction of the applied electric field by the Coulomb force between the dipole moment of the organic nonlinear optical dye and the applied electric field.

  In the electric field poling method, in general, the organic nonlinear optical dye is promoted to move in the electric field direction by heating to a temperature in the vicinity of the high Tg polymer while an electric field is applied. After sufficient alignment is induced, the applied electric field is removed after cooling to room temperature with the electric field applied and freezing the alignment.

The temperature of the poling treatment is appropriately selected according to the type of the high Tg polymer. From the viewpoint of further suppressing thermal decomposition and thermal denaturation of the organic nonlinear optical dye, it is preferably set to 190 ° C. or lower. Further, the temperature of the poling treatment is usually 70 ° C. or higher, and more preferably 100 ° C. or higher.
Although there is no restriction | limiting in particular in the processing time of a polling process, 1 to 60 minutes are preferable and 1 to 20 minutes are more preferable.

As an index for confirming the alignment state of the organic nonlinear optical dye, there is a numerical value (order parameter: φ) indicating how many organic nonlinear optical dyes are aligned in the electric field direction. Order parameter, when the absorbance when the orientation of the molecules of the organic nonlinear optical dyes are oriented the absorbance when the random A _0, in the direction of the electric field (the thickness direction) was set to A _t, φ = 1- (A _t / A ₀ ).
The order parameter is a numerical value that is 1 in an ideal state in which all molecules are perfectly oriented, and 0 when completely random, and indicates that the larger the value, the higher the degree of molecular orientation as a whole. By measuring this value, it can be determined how efficiently polling has been performed, and its stability can be evaluated.

  The film thickness of the nonlinear optical film of the present invention is appropriately adjusted depending on the application, and is not limited at all. The film thickness is practically 100 to 5000 nm, and usually 500 to 3000 nm.

[Optical element]
The optical element of the present invention is an element that uses the nonlinear optical material of the present invention and operates based on the nonlinear optical effect. The optical element of the present invention preferably has the nonlinear optical film of the present invention. Specific examples of the optical element of the present invention include a wavelength conversion element, a photorefractive element, an electro-optical element, and the like. Particularly preferred are electro-optical elements such as optical switches, optical modulators (optical modulation elements), phase shifters and the like that operate based on the electro-optical effect.

The electro-optical element is preferably used as an element having a structure in which the nonlinear optical film of the present invention is formed on a substrate and sandwiched between electrode pairs for input electric signals.
As a material constituting such a substrate, metals such as aluminum, gold, iron, nickel, chromium, and titanium; semiconductors such as silicon, titanium oxide, zinc oxide, and gallium-arsenic; glass; polyethylene terephthalate, polyethylene naphthalate, Plastics such as polycarbonate, polysulfone, polyetherketone, polyimide, etc. can be used.

  A conductive film may be formed on the surface of these substrate materials, and examples of the conductive film material include metals such as aluminum, gold, nickel, chromium, and titanium; tin oxide, indium oxide, ITO (oxidized Conductive oxides such as tin-indium oxide composite oxide) and IZO (indium oxide-zinc oxide composite oxide); conductive polymers such as polythiophene, polyaniline, polyparaphenylene vinylene, and polyacetylene are used. These conductive films are formed by using a known dry film forming method such as vapor deposition or sputtering, or a known wet film forming method such as dip coating or electrolytic deposition, and a pattern is formed as necessary. May be. Note that the conductive substrate or the conductive film formed on the substrate as described above is used as an electrode at the time of polling or operation as an element (hereinafter abbreviated as “lower electrode”).

  The substrate surface is further provided with an adhesive layer for improving the adhesion between the film formed on the substrate and the substrate, a leveling layer for smoothing irregularities on the substrate surface, or these functions, if necessary. Some intermediate layer provided in a lump may be formed. The material for forming such a film is not particularly limited, and examples thereof include acrylic resins, methacrylic resins, amide resins, vinyl chloride resins, vinyl acetate resins, phenol resins, urethane resins, vinyl alcohol resins, acetal resins, and the like. Known products such as a crosslinked product of zirconium chelate compound, titanium chelate compound, silane coupling agent and the like, and a co-crosslinked product thereof can be used.

  The electro-optical element is preferably formed to include a waveguide structure, and the nonlinear optical film of the present invention is particularly preferably included in the core layer of the waveguide.

  A clad layer (hereinafter abbreviated as “lower clad layer”) may be formed between the core layer containing the nonlinear optical film of the present invention and the substrate. The lower cladding layer may be any layer as long as it has a lower refractive index than the core layer and is not affected by the formation of the core layer. As such materials, UV curable or thermosetting resins such as acrylic, epoxy, oxetane, thiirane, and silicone; polyimide; glass and the like are preferably used.

  After forming the core layer by the nonlinear optical film of the present invention, a clad layer (hereinafter, abbreviated as “upper clad layer”) may be further formed in the same manner as the lower clad layer. As a result, a slab waveguide having a structure of substrate / lower cladding layer / core layer / upper cladding layer is formed.

  After forming the core layer, the core layer is patterned by a known method using a semiconductor process technology such as reactive ion etching (RIE), photolithography, electron beam lithography, etc. to form a channel type waveguide or a ridge type waveguide You can also Alternatively, a channel-type waveguide can be formed by changing the refractive index of the irradiated portion by patterning and irradiating a part of the core layer with UV light, an electron beam or the like.

  A basic electro-optic element is formed by forming an electrode (hereinafter referred to as “upper electrode”) for applying an input electric signal to the surface of the upper clad layer in a desired region of the upper clad layer. be able to.

  When forming a channel-type waveguide or a ridge-type waveguide as described above, the core layer pattern may be a known device structure such as a linear type, a Y-branch type, a directional coupler type, or a Mach-Zehnder type. It can be configured, and can be applied to known optical information communication devices such as an optical switch, an optical modulator, and a phase shifter.

  The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples.

Synthesis Example 1 Synthesis of Organic Nonlinear Optical Dye-1 <Synthesis of Organic Nonlinear Optical Dye-c4>
With reference to the example of Japanese Patent No. 5826206, an organic nonlinear optical dye-c4 having the following structure was synthesized.

<Synthesis of Compound M-1>
Compound M-1 was synthesized according to the following scheme.

  10 g of butanediol (manufactured by Tokyo Chemical Industry) and 10 ml of 2-ethylhexanoyl chloride (manufactured by Tokyo Chemical Industry) were added to 60 mL of toluene, and then 11.2 g of sodium hydrogen carbonate was added under ice water, followed by stirring for 2 hours. Thereafter, water was added, and organic substances were extracted with ethyl acetate. After drying with magnesium sulfate, the organic solvent was distilled off under reduced pressure to obtain Compound M-1.

<Synthesis of Organic Nonlinear Optical Dye-1>
After 0.7 g of the organic nonlinear optical dye-c4 obtained above and 0.7 g of the compound M-1 obtained above were dissolved in 10 ml of THF, 0.4 g of triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) Was added. Thereafter, 0.7 ml of diethyl azodicarboxylate (DEAD) 30% toluene solution (manufactured by Tokyo Chemical Industry) was added at room temperature, and the mixture was stirred at room temperature for 3 hours. Thereafter, water was added, and the resulting residue was filtered off and purified using a silica gel chromatography column (eluent, chloroform) to obtain 0.34 g of organic nonlinear optical dye-1 (green solid).
It was confirmed by NMR analysis that the organic nonlinear optical dye-1 had a structure represented by the following structural formula.

^１Ｈ ＮＭＲ（ＣＤＣｌ_３）δ８．８２（ｄ，１Ｈ）、７．９５（ｄ，２Ｈ）、７．８０ （ｄ，２Ｈ）、７．６９（ｍ，３Ｈ）、７．０３（ｄ，１Ｈ）、６．８０（ｄ，２Ｈ）、 ４．３０（ｔ，４Ｈ）、４．２０（ｔ、２Ｈ）、３．４７（ｔ，２Ｈ）、２．２７（ｍ， １Ｈ）、１．９０（ｍ、２Ｈ）、１．７０（ｍ、２Ｈ）、１．２〜１．６（ｍ，２６Ｈ）、０．８０−１．０５（ｍ，１８Ｈ）ｐｐｍ

¹ H NMR (CDCl ₃ ) δ 8.82 (d, 1H), 7.95 (d, 2H), 7.80 (d, 2H), 7.69 (m, 3H), 7.03 (d, 1H) ), 6.80 (d, 2H), 4.30 (t, 4H), 4.20 (t, 2H), 3.47 (t, 2H), 2.27 (m, 1H), 1.90. (M, 2H), 1.70 (m, 2H), 1.2-1.6 (m, 26H), 0.80-1.05 (m, 18H) ppm

[Synthesis Example 2] Synthesis of Organic Nonlinear Optical Dye-2 Organic Nonlinear Optical Dye-in the same manner as in Synthesis Example 1 except that the following compound M-2 was used in place of compound M-1 in the above synthesis example 1. 2 was obtained.
It was confirmed by NMR analysis that the obtained organic nonlinear optical dye-2 had a structure represented by the following structural formula.

[Synthesis Example 3] Synthesis of Organic Nonlinear Optical Dye-3 In the above Synthesis Example 1, organic nonlinear optics was obtained in the same manner as Synthesis Example 1 except that 2-ethyl-1-hexanol was used instead of Compound M-1. Dye-3 was obtained.
It was confirmed by NMR analysis that the obtained organic nonlinear optical dye-3 had a structure represented by the following structural formula.

[Comparative Synthesis Examples 1 to 8] Synthesis of Organic Nonlinear Optical Dyes-c1 to c3 and c5 to c9 According to Synthesis Example 1, organic nonlinear optical dyes -c1 to c3 and c5 to c9 shown below were synthesized. The structures of organic nonlinear optical dyes-c1 to c9 are shown below.

Example 1 Production of Nonlinear Optical Film-1A The organic nonlinear optical dye-1 and polymethyl methacrylate (PMMA, weight average molecular weight: 120,000, Tg: 120 ° C.) having a solid content concentration of 14% by mass (dye And PMMA were dissolved in cyclopentanone so that the mass ratio of pigment and PMMA was 15/85) to obtain a solution of nonlinear optical material-1A.
On the glass substrate (5 cm × 5 cm) provided with an ITO layer on the surface, the nonlinear optical material-1 is applied by spin coating as described above, and dried at 120 ° C. for 1 hour to form a nonlinear optical film-1A having a thickness of 2 μm. Obtained.

Example 2 Production of Nonlinear Optical Film-2
In Example 1, nonlinear optical film-2 was obtained in the same manner as in Example 1 except that organic nonlinear optical dye-2 was used instead of organic nonlinear optical dye-1.

Example 3 Preparation of Nonlinear Optical Film-3 In Example 1 above, nonlinear optics was used in the same manner as Example 1 except that organic nonlinear optical dye-3 was used instead of organic nonlinear optical dye-1. Membrane-3 was obtained.

Example 4 Production of Nonlinear Optical Film-1B In Example 1 above, instead of PMMA, polycarbonate (trade name: Iupizeta PCZ-300, manufactured by Mitsubishi Gas Chemical Company, weight average molecular weight: 30000, Tg: 185 ° C.) The non-linear optics was used in the same manner as in Example 1 except that the solid content concentration in cyclopentanone was 10% by mass (the content ratio of the dye and the polycarbonate was dye / polycarbonate = 7/93). Membrane-1B was obtained.

[Comparative Example 1] Production of Nonlinear Optical Film-c1 Nonlinear optics was obtained in the same manner as in Example 1 except that organic nonlinear optical dye-c1 was used in place of organic nonlinear optical dye-1. Membrane-c1 was obtained.

Comparative Example 2 Production of Nonlinear Optical Film-c2 Nonlinear optics in the same manner as in Example 1 above, except that organic nonlinear optical dye-c2 was used in place of organic nonlinear optical dye-1. Membrane-c2 was obtained.

Comparative Example 3 Production of Nonlinear Optical Film-c3 Nonlinear optics in the same manner as in Example 1 above, except that organic nonlinear optical dye-c3 was used in place of organic nonlinear optical dye-1. Membrane-c3 was obtained.

Comparative Example 4 Production of Nonlinear Optical Film-c4 Nonlinear optics in the same manner as in Example 1 except that organic nonlinear optical dye-c4 was used in place of organic nonlinear optical dye-1. Membrane-c4 was obtained.

Comparative Example 5 Production of Nonlinear Optical Film-c5 Nonlinear optics in the same manner as in Example 1 except that organic nonlinear optical dye-c5 was used in place of organic nonlinear optical dye-1. Membrane-c5 was obtained.

Comparative Example 6 Production of Nonlinear Optical Film-c6 Nonlinear optics in the same manner as in Example 1 except that organic nonlinear optical dye-c6 was used in place of organic nonlinear optical dye-1. Membrane-c6 was obtained.

[Comparative Example 7] Production of nonlinear optical film-c7 In Example 1 above, nonlinear optics was used in the same manner as Example 1 except that organic nonlinear optical dye-c7 was used instead of organic nonlinear optical dye-1. Membrane-c7 was obtained.

Comparative Example 8 Production of Nonlinear Optical Film-c8 Nonlinear optics in the same manner as in Example 1 except that organic nonlinear optical dye-c8 was used in place of organic nonlinear optical dye-1. Membrane-c8 was obtained.

[Comparative Example 9] Production of Nonlinear Optical Film-c9 In Example 1, nonlinear optics was used in the same manner as Example 1 except that organic nonlinear optical dye-c9 was used instead of organic nonlinear optical dye-1. Membrane-c9 was obtained.

[Test Example 1] Evaluation of nonlinear optical performance For each organic nonlinear optical dye obtained in each of the above synthesis examples and comparative synthesis examples, the AM1 method was used by a quantum chemistry calculation program (trade name: SCIGRESS, manufactured by Fujitsu Limited). Thus, the hyperpolarizability β was calculated, and the nonlinear optical performance was evaluated based on the following evaluation criteria. The results are shown in the table below. It can be said that the higher the hyperpolarizability β, the higher the nonlinear optical activity.
<Evaluation criteria for nonlinear optical performance>
A: The value of hyperpolarizability β is 150 or more B: The value of hyperpolarizability β is 140 or more and less than 150 C: The value of hyperpolarizability β is 130 or more and less than 140 D: The value of hyperpolarizability β is less than 130 The nonlinear optical performance of the organic nonlinear optical dye is preferably an evaluation A.

[Test Example 2] Evaluation of wet heat resistance The absorption spectrum in the visible region of the nonlinear optical films of the above Examples and Comparative Examples was measured using a visible infrared polarization spectrophotometer (trade name: V-670ST, manufactured by JASCO Corporation). And measured.
Next, each nonlinear optical film was stored for 2000 hours under high temperature and high humidity conditions (85 ° C., relative humidity 85%). After this storage, the absorption spectrum in the visible region of each nonlinear optical film was measured in the same manner as described above. Based on the obtained absorption spectrum, the dye retention (X%) after storage was calculated by the following formula, and the wet heat resistance was evaluated according to the following evaluation criteria. The results are shown in the table below.

X (%) = 100 × D _t / A ₀
D _t : Absorbance at a wavelength λmax of the nonlinear optical film after storage under the above-mentioned high-temperature and high-humidity conditions A ₀ : Absorbance at a wavelength λmax of the nonlinear optical film before storage under the above-mentioned high-temperature and high-humidity conditions

<Evaluation criteria for wet heat resistance>
A: X is 95% or more B: X is 90% or more and less than 95% C: X is 85% or more and less than 90% D: X is less than 85% Practically, the wet heat resistance is preferably evaluation A.

[Test Example 3] Evaluation of light resistance The absorption spectrum in the visible region of the nonlinear optical film of each of the above Examples and Comparative Examples was measured using a visible infrared polarization spectrophotometer (trade name: V-670ST, manufactured by JASCO Corporation). And measured.
Subsequently, 365 nm ultraviolet rays (UV) were irradiated for 10 minutes using a high-output ultraviolet UV-LED tabletop spotlight (trade name: LED365-SPT, manufactured by Optcord). At that time, UV irradiation was performed with the UV irradiation surface of the spotlight in close contact with the nonlinear optical film (irradiation amount: 187 mW). After this UV irradiation, the absorption spectrum in the visible region of each nonlinear optical film was measured in the same manner as described above. Based on the obtained absorption spectrum, the dye retention (Y%) after UV irradiation was calculated by the following formula, and the wet heat resistance was evaluated according to the following evaluation criteria. The results are shown in the table below.

Y (%) = 100 × E _t / A ₀
E _t : Absorbance at a wavelength λmax of the nonlinear optical film after UV irradiation A ₀ : Absorbance at a wavelength λmax of the nonlinear optical film before UV irradiation

<Evaluation criteria for light resistance>
A: Y is 99% or more B: Y is 95% or more and less than 99% C: Y is 90% or more and less than 95% D: Y is less than 90% In practice, the light resistance is preferably evaluation A.

As shown in Table 2, also R ³ in the general formula (1) is a dye which is a substituted group, if the R ³ is not in the form of an unsubstituted branched alkyl group, the dye is in non-linear optical properties Was superior to both wet heat resistance and light resistance (Comparative Examples 1 and 9).
Moreover, the pigment | dye whose R < ³ > is not a substituent but a hydrogen atom in General formula (1) cannot satisfy | fill both wet-heat-resistance and light resistance property favorably (Comparative Examples 4-7). Similarly, in the case where R ¹ and R ² in formula (1) are not an unsubstituted branched alkyl group but a linear alkyl group or a linear substituted alkyl group, it is not possible to satisfactorily achieve both wet heat resistance and light resistance. (Comparative Example 2).
Furthermore, when R ^{1 to} R ^{3 in the} general formula (1) are not a group defined by the general formula (1), the nonlinear optical performance is inferior regardless of the form of L, and the wet heat resistance and light resistance are good. (Comparative Examples 3 and 8).

  On the other hand, it was found that all of the dyes of the general formula (1) which are the organic nonlinear optical dyes of the present invention are excellent in nonlinear optical performance and can realize both high heat resistance and light resistance at a high level (Example 1). -4) Moreover, as a result of estimating the compatibility between the nonlinear optical dye and the binder (the above-mentioned PMMA and polycarbonate) using the HANSEN solubility parameter calculation software, all of the organic nonlinear optical dyes of the present invention are compatible with the matrix. Was found to be very good.

Claims (7)

An organic nonlinear optical dye represented by the following general formula (II) .

In the general formula (II) , R ¹ and R ² represent an unsubstituted branched alkyl group, and R ³ represents a group having an unsubstituted branched alkyl group. R ^{4 to} R ⁷ represent a hydrogen atom or an alkyl group. The organic nonlinear optical dye according to claim 1 , wherein R ^{4 to} R ⁷ are hydrogen atoms. A nonlinear optical material comprising the organic nonlinear optical dye according to claim 1 or 2 and a polymer having a glass transition temperature of 100 ° C. or higher. In the nonlinear optical material, the ratio of the content of the organic nonlinear optical dye in the total content of the organic nonlinear optical dye and the polymer having a glass transition temperature of 100 ° C. or higher is 10 to 50% by mass. The nonlinear optical material according to claim 3 . Nonlinear optical film using a nonlinear optical material according to claim 3 or 4. Optical element using a nonlinear optical material according to claim 3 or 4. The optical element according to claim 6 , wherein the optical element is a light modulation element.