Matsushita Electric Industrial Co., Ltd.

Director-general of the Agency of Industrial Science and Technology

Eiji Ando

Junichi Hibino

Jinsei Miyazaki

Kazuhisa Morimoto

Kimiaki Yoshino

Isao Takeshita

Yoshiki Goto

Hiroyoshi Tanaka

Kumiko Moriyama

Nobuhiko Wakamatsu

Masaaki Suzuki

Masa-aki Suzuki

Takashi Hashida

Shiro Hozumi

Yoshiki Hayashi

Yosio Okahata

Kunio Hirao

The present invention provides a photochromic material which comprises a spiropyran compound of formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are independently alkyl groups each containing 1 to 30 carbon atoms and Y is a halogen. The photochromic material possesses absorption sensitivity at wavelengths in the length region of about 700 nm which is the oscillation range of a semi-conductor laser device, and possesses higher stability compared with conventional one when it becomes a colored form.

Photochromic material and an optical storage medium using the same

A photochromic material having a thin film of an ion complex of a photochromic substance having an anionic group and a cationic surface active agent is described. Since the surface active agent is used, a uniform film with good photochromism can be obtained. A method for fabricating the photochromic material is also described.

Photochromic materials having a thin photochromic film and a method for

Novel photochromic spiropyran compounds having an absorption sensitivity in a longer wavelength region than known photochromic compounds are provided. The novel spiropyran compounds have a spiropyran skeleton having a methoxy group at the 6 position, a nitro group at the 8 position, a bromine atom at the 5' and 7' positions, and an alkyl group at the 1' position.

Photochromic spiropyran compounds

The present invention provides a photochromic material possessing absorption sensitivity in a longer wavelength region when compared with conventional photochromic materials. The photochromic material is a spiropyran compound having a methoxy group at the 6 position, nitro groups at the 8 and 5' positions, and an alkyl group at the 1' position of the spiropyran skeleton as shown below: ##STR1##

Photochromic dinitrated spiropyrans

An optical storage medium comprising a recording layer containing organic dye molecules which allows recording due to change in the molecular structure or molecular aggregate structure induced by irradiation with light, and a stable controlling layer formed on the recording layer, which controlling layer is stable against the irradiation by the lights for recording or reading out. A multi-frequency optical storage medium comprises a plurality of a combination of the recording layers and the controlling layer as a separating layer.

Optical storage medium

A process for preparing photochromic spiropyran compounds having a halogen atom or atoms and a hydrophobic alkyl group wherein a starting photochromic spiropyran compound having the hydrophobic alkyl group is reacted directly with a halogenating agent in a solvent. This reaction efficiently proceeds with the product being obtained in high yield.

Process for the preparation of photochromic spiropyran compounds

The optical storage medium of the present invention comprises: (1) a substrate; (2) ultra-thin recording layers containing a dye; and (3) controlling layers. The recording layers and the controlling layers are accumulated alternately, and the uppermost layer is a controlling layer. The optical storage medium of the present invention contains dye cohesions in the recording layer in an extremely small amount and of extremely small size so that the medium can store a high density of records.

Optical storage media

A lubricant for recording media having excellent sliding characteristics and abrasion resistance is obtained when an alkylsilane of the following formula (I) is prepared in a thin layer with the LB method: ##STR1## Example of the alkylsilane include .gamma.-(N,N-dioctadecylsuccinylamino)propyltriethoxysilane and .gamma.-[N-[tris-(heptadecylyloxymethyl)] methylsuccinylamino]-propyltriethoxysilane.

Method of preparing lubricant for recording media

A long-chain keto group is introduced into the molecule of furylfulgide hng no hydrophobic group to procure a good balance of hydrophilicity and hydrophobicity, thereby making it possible to obtain a uniform ultra-thin film optical recording medium having photochromism of fulgide according to spin coating method or Langmuir-Blodgett method.

Optical recording medium and process for producing the same

The invention provides an optical recording medium comprising a Langmuir-dgett film made from a mixture of a photochromic compound of the following formula, in which a carboxyl group and an alkyl group have been introduced to the 8-position and the 1'-position, respectively, at the same time, and a long-chain carboxylic acid: ##STR1## wherein R represents a hydrocarbon having 5 to 31 carbon atoms.

Optical recording medium

An optical recording medium which comprises a substrate and a recording layer of at least two J-aggregates of dyes formed on the substrate is described. The dyes may be photochromic dyes or other types of dyes capable of forming the aggregates which have narrower absorption spectral ranges than original dyes. A plurality of information bits can be written in the recording layer by irradiation of one laser beam spot. The recording layer is formed by an LB film method or a method capable of fluidizing a dye solution in a direction horizontal to the substrate surface. A recording method using the medium is also described.

Method for recording optical information in optical high density

A long-chain keto group is introduced into the molecule of furylfulgide hng no hydrophobic group to procure a good balance of hydrophilicity and hydrophobicity, thereby making it possible to obtain a uniform ultra-thin film optical recording medium having photochromism of fulgide according to spin coating method of Langmuir-Blodgett method.

The invention provides a photochromic material characterized by an improvnt in balance of the substituents in the conventional furylfulgides and represented by the general formula: ##STR1## (wherein R represents an alkyl chain having 5 to 31 carbon atoms). According to this molecular structure, a mutually appropriate steric hindrance is induced between the isopropylidence group and the long-chain alkyl group to make the regio isomer unstable, thus preventing the regio isomer from being by-produced while also inhibiting any isomerization reaction from occuring in the synthesis of the fulgide. Further, a good balance of hydrophilic part and hydrophobic part is produced to facilitate formation of a Langmuir-Blodgett film.

Certain photochromic fulgide compounds and method for their synthesis

An optical recording medium is prepared by the use of spiropyrane whose molecular structure contains an alkyl chain having at least 10 more carbon atoms, and by the use of an LB film method or a spin coating method. This recording medium is of a structure wherein when irradiated with the UV, the spiropyrane is photo-isomerized to photomerocyane and, thereafter, when subsequently heated at 35.degree. to 40.degree. C. for 15 minutes, a J-aggregate of the photomerocyane is formed in very stabilized form. When the recording medium is irradiated with light of wavelength of visible spectrum, the color is bleached with the information consequently recorded. The optical recording medium herein disclosed is rewritable and can retain the recorded information for 5,000 hours or more.

A optical recording medium which comprises a substrate and a recording layer of at least two J-aggregates of dyes formed on the substrate is described. The dyes may be photochromic dyes or other types of dyes capable of forming the aggregates which have narrower absorption spectral ranges than original dyes. A plurality of information bits can be written in the recording layer by irradiation of one laser beam spot. The recording layer is formed by an LB film method or a method capable of fluidizing a dye solution in a direction horizontal to the substrate surface. A recording method using the medium is also described.

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Katano, Japan

Eiji Ando