JPS63241543A - Photochromic optical storage material - Google Patents

Abstract

PURPOSE:To enable quick storage, reading, erasing, and preservation of storage for a long time by using a film having a bimolecular film structure obtnd. from an ion complex of an ionic surface active agent having two linear higher alkyl groups with a high molecular electrolyte having counter electric charge. CONSTITUTION:A film having a bimolecular film structure obtnd. from an ion complex of an ionic surface active agent having two linear higher alkyl groups with a high molecular electrolyte having counter electric charge, is used as the high molecular material film of this invention. Suitable high molecular electrolyte is, for example, polystyrenic electrolyte, polyvinyl sulfate, polyglutamic acid, heparin, polylysine, polyallylamine, etc. By this constitution, optical storage, reading, erasing are executed quickly, and long time preservation of optical storage is also possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel photochromic optical recording material. More specifically, the present invention is suitable for use in, for example, ultra-large capacity storage devices compatible with ultra-large computers, ultra-small disk devices for business and home use, and high-resolution display devices that are optical information processing peripherals. This invention relates to high-performance photochromic optical recording materials.

Conventional technology Optical recording materials that use photochromism, a phenomenon in which the color changes when exposed to light and returns to its original color when heated or exposed to light of a different wavelength, do not require development and can be used repeatedly. Not only is it possible, but it also has high resolution and, in principle, the recording density can be increased ten times higher than the limit of 100 million bits per l, which is the limit of conventional recording methods. It has started to attract attention from all walks of life.

Such photochromic optical recording materials require compounds with photochromic properties, so-called photochromic compounds. Until now, photochromic compounds such as dimethylene succinic anhydride derivatives, spirobenzopyrans, and spirooxazines have been used. and azobenzenes. Among these, spirobenzobilanes have advantages such as a large difference in absorption spectra before and after light irradiation, an extremely high molecular extinction coefficient for a single colored substance, high coloring efficiency, and high readout accuracy. Therefore, it is particularly preferable as a material for optical recording materials.

However, this spirobenzobira 7Mn has a type of 7 otochromism and can be recorded, read, and erased by light, but when used as a recording material,
Even if it is recorded as a colored type, it has the disadvantage that it is not suitable for long-term storage because it returns to the colorless closed ring type when heated.

In order to improve these drawbacks, attempts have been made so far to disperse the spirobenzobilanes in a suitable binder resin such as polystyrene, polymethyl acrylate, polymethyl methacrylate, or the like. however,
In this method, the thermal movement of the spirobenzobilanes in the resin is significantly restricted, so the rate of thermal fading can be suppressed to several tenths to several hundredths of that in the total solution. , which is inevitably disadvantageous in terms of rapid recording, reading, and erasing, which is another desirable property for optical recording materials.

In order to achieve both of these properties, which are contradictory in principle, such as rapid recording, reading, and erasing, and long-term preservation of records, a conventionally known polymer binder is used, and the spirobenzobilanes are added to the binder. This cannot be achieved by completely dispersing it.

Problems to be Solved by the Invention Under these circumstances, the present invention uses spirobenzopyrans, which can quickly record, read, and erase with light, and can preserve records for a long time. It was developed with the aim of providing a complete range of photochromic optical recording materials.

Means for Solving the Problems The present inventors have conducted extensive research in order to develop a new photochromic recording material that simultaneously satisfies the conflicting demands of rapid recording, reading, and erasing, and long-term preservation of records. As a result of this, it is only necessary to cause a change in the physical state of the polymer binder by stimulation other than light, such as heat, and to arbitrarily control the state in which the photochromic reaction progresses and the state in which it is reversed. It has been discovered that a particular polymer film with a bilayer membrane structure is effective for this purpose, and that if spirobenzopyrans are dispersed as a photochromic compound in this polymer film, all of the above objectives can be achieved. Based on this knowledge, the present invention was completed.

That is, the present invention provides an optical recording material comprising spirobenzobilanes as a photochromic compound dispersed in a polymer film, in which the polymer film is an ionic surfactant having a linear higher alkyl group 2@. The present invention provides a photochromic optical recording material characterized by using a film having a bilayer structure obtained from an ionic complex of an agent and a polymer electrolyte having an opposite charge.

The present invention will be explained in detail below.

In the optical recording material of the present invention, spirobenzobilanes used as photochromic compounds have the following general formula (wherein R1 is a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, an amine group, or an amino group having a substituent group). group, R2 is an alkyl group, R3 is a nitro group or a halogen atom). Such spirobenzopyrans are well known and include those represented by the formula Q)i5.

When these spirobenzobilanes are exposed to ultraviolet light, they change from a colorless ring-closed form to a colored open-ring form, and this open-ring form changes to a colorless closed-ring form when exposed to visible light or heat, a phenomenon known as photochromism. I'm doing sex 5CM.

In the optical recording material of the present invention, the polymer film is a bilayer film obtained from an ionic complex of an ionic surfactant having two linear higher alkyl groups and a polymer electrolyte having an opposite charge. A structured film is used.

The ionic surfactant residue may be, for example, a compound of the general formula (in which R1 and R2 are each a linear alkyl group having 12 or more carbon atoms, and they may be the same and C or each other may be They may be different (R and R4 are each a lower alkyl group, and they may be the same or different from each other). , but not limited to, linear higher alkyl groups 2fllH
- Ionic surfactants having other structures can also be used.

On the other hand, as the polymer electrolyte, one having an opposite charge to the above-mentioned ionic surfactant is used. Examples of such polymer electrolytes include polystyrene electrolytes, polyvinyl sulfate, polyglutamic acid, heparin, polylysine, and polyallylamine. Examples of the residue of the polystyrene electrolyte include those represented by the general formula (where m is an integer of 10 or more).

These polymer electrolytes are appropriately selected depending on the type of corresponding ionic surfactant.

The optical recording material of the present invention is usually produced by a casting method. For example, after dissolving the above-mentioned ionic complex of spirobenzobilane, ionic surfactant, and polymer electrolyte in a suitable organic solvent in a desired ratio, this solution is cast or cast onto a support. By coating and drying, the optical recording material of the present invention comprising the spirobenzopyran dispersed in a polymer film can be obtained.

At this time, the organic solvent used includes, for example, chlorinated solvents such as OIform and dichloroethane, and alkanes such as hexane and decane, with chloroform being particularly preferred. These solvents may be used alone or in combination of two or more. As the support, for example, a glass plate, a quartz plate, a metal plate, a plastic plate made of polymethyl acrylate, polymethyl methacrylate, polycarbonate, polyamide, polyester, etc. can be used.

Furthermore, regarding the ratio of the ionic complex of the ionic surfactant and the polymer electrolyte to the spirobenzobilanes, the proportion of the spirobenzobilanes to 100 parts by weight of the ionic complex is usually 0.05 to 1 part by weight. Used in percentages. Further, the film thickness of the optical recording material is usually 0.
It is selected in the range of 001-0.1111.

The optical recording material of the present invention obtained in this manner has spirobenzobilanes dispersed in a polymer film having a bilayer structure, and the bilayer structure has been recognized as '1M by X-ray diffraction. can do. Furthermore, the polymer film having the bilayer structure exhibits phase transition behavior in the material (referred to as phase transition temperature 'jzTc), which can be confirmed by differential scanning calorimetry measurement. In this material, at low temperatures below Tc, the polymer film assumes a lamellar crystalline state with low molecular mobility, while at high temperatures above Tc, it assumes a smectic liquid crystal-like precipitate with high mobility.

Therefore, it is observed that the thermal fading reaction rate of this optical recording material after irradiation with ultraviolet light changes discontinuously and greatly around the Tc temperature, and is 3 to 8 times faster at temperatures above Tc than at temperatures below Tc. It was done. Is this change in reactivity greater than Tc? -It was reversible by repeated temperatures below TC.

In addition, in order to control reactivity through phase change, it is necessary that the bilayer structure of the polymer film is well developed, and generally speaking, the degree of development of the bilayer structure in the cast state is limited. Although it is low, at a temperature higher than Tc,
If left in an atmosphere with a relative humidity of 100 degrees for several hours, the bilayer structure will develop better.

Since the optical recording material of the present invention has the above-mentioned properties, erasing or recording can be performed quickly by irradiating visible light or ultraviolet light at a high temperature higher than Tc, and recording can be stored at Tc or higher. It can be carried out stably by keeping the temperature at the following low temperature.

Effects of the Invention The photochromic optical recording material of the present invention has two effects: light and heat.
It responds to the physical stimulus of a species, and can be recorded, read out, and erased arbitrarily and quickly, as well as long-term storage of records, such as an ultra-large capacity storage device compatible with an ultra-large computer. It can be suitably used in fields such as ultra-small disk devices for business and home use, and high-resolution display devices that are peripheral devices for optical information processing.

It can also be used in applications such as heat-responsive optical filters and toys.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 In 1 tnt of chloroform, an ionic complex of dioctadecyldimethylammonium and polystyrene sulfonic acid was prepared with 50 μl and 1', 1', 3'-)methyl-6-nitrosip[:2H-1-pensohylan-2.
2'-indoline] was dissolved and cast on a quartz plate at room temperature for 3 to 4 hours to a thickness of 0.0
An optical recording material consisting of 1 m of transparent film was obtained. This material was then left for 1 hour at 60° C. and 100% relative humidity. It was confirmed by X-ray diffraction and differential scanning calorimetry (DSC) that the bilayer structure was well developed by this heat treatment.

As a result of the heat treatment, the diffraction image of 39A attributed to bilayer membrane lamellae was observed more clearly in X-ray diffraction, and p
The endothermic peak during the temperature increase process in SC measurement shifts from 39°C to 49°C, and the enthalpy change (
ΔH) is 2.6 kcal/mol to 10.4 k
Cal/mol increased.

Furthermore, this optical recording material showed good photochromism. In other words, light from a 500W ultra-high pressure mercury lamp,
Corning colored glass filters -7-51 and 3-
When UV light and visible light are irradiated alternately using 73'i,
Upon irradiation with ultraviolet light, visible absorption (purple color) with a peak at a wavelength of 558 nm appeared, and upon irradiation with 'E+J visual light, the material became colorless again.

The coloring after irradiation with ultraviolet light also fades due to heat, but the rate of thermal fading in the film is several tenths of a second lower than in organic solvents such as acetone, which is clearly due to the photochromic reaction of the spirobenzopyran compound. It can be seen that this is suppressed by constraints from the film material.

The polymer film having a bilayer structure in this optical recording material exhibits a crystal-liquid crystal phase transition at 49° C., but the rate of thermal fading from coloring changes significantly above and below this temperature. The first-order reaction rate constant of the main component during color fading is T
5℃ from 47.5℃ below c to 52.5℃ above Tc
From 1.0 x 10/S to 5.5 x 1 with temperature change of
It increased 5.5 times to 0/S. On the other hand, with a temperature change of 5°C in the temperature range outside the phase transition temperature, the speed change is only 1.2 to 2 times, so the large speed change near Tc is attributed to the phase transition of the bilayer membrane. It is clear that this is due to this. This large change in fading rate is greater than Tc #Tc
A of the following temperatures! The change was reversible by reversing.

The accompanying drawing is a graph (Arrhenius plot) showing the relationship of the logarithm of the -order rate constant to the reciprocal of temperature, and is shown as a solid line for the above-mentioned recording material.

Further, an optical recording material was produced in the same manner using the following compound as a spirobenzopyran compound. The magnitude of the change in fading rate near Tc for these materials is as follows.

Spirobenzopyran compound k (Tc or more)/k
(Tc or less) H5 H3 Comparative Example In 2 fIt of a mixed solvent of toluene and benzene, polymethyl methacrylate 100~, 1L, 1', 3/-
0.2 μm of trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-indoline] was dissolved, placed on a glass plate using a spinner at 1100 rpm, and dried under reduced pressure at room temperature for 3 hours.

Regarding this sample, the fading rate was measured in the temperature range of 30 to 60°C in the same manner as in the examples. Polymethyl methacrylate films do not exhibit phase transition behavior in the 30-60'CcDm degree range, so no rapid fading rate changes were observed.

The Arrhenius plot for the recording material obtained in this example is indicated by a dashed line in the drawing.

[Brief explanation of drawings]

The first page is a graph showing an Arrhenius plot from a colored type to a colorless type of spirobenzobilane in polymer films in Examples and Comparative Examples.

Claims (1)

[Claims] 1. An optical recording material comprising a spirobenzopyran as a photochromic compound dispersed in a polymer film, in which the polymer film contains an ionic surfactant having two linear higher alkyl groups and an oppositely charged ionic surfactant. 1. A photochromic optical recording material characterized by using a film having a bilayer structure obtained by an ion complex with a polymer electrolyte having the following properties.