Imperial Chemical Industries Limited

Tdk Corporation

Paul F Gordon

Simon Allen

John O Morley

Damien Gerard McDonnell

Richard A Hann

David J Thompson

Peter J Duggan

Anthony J Hughes

Brian Bothwell

Akihiko Kuroiwa

Toshiki Aoi

Joseph Zyss

Stephen J Abbott

Tezumbumi Kamijo

A pit-forming optical recording medium comprises a substrate supporting a film of optically deformable recording material comprising an organic dye for absorbing optical signals of modulated electromagnetic radiation applied to the film and thereby causing corresponding deformations of the film when the signal intensities exceed predetermined threshold levels. The dye is a phthalocyanine compound or mixture of phtalocyanine compounds in which each of at least five of the peripheral carbon atoms in the 1, 4, 5, 8,9, 12, 13 or 16 positions (the '3,6-positions') of the phthalocyanine nucleus, as shown in Formula I, is linked by an atom from Group VB or Group VIB of the Periodic Table to a carbon atom of an organic radical. In preferred compounds each of the eight 3,6-positions is linked by an atom from Group VB or Group VIB, especially sulphur, selenium or nitrogen, to an organic radical. ##STR1##

A pit-forming optical recording media and process for producing the same

An azo compound of the formula: ##STR1## wherein R is an non-hydrophilic aliphatic or cycloaliphatic group containing from 8 to 40 carbon atoms;

Azo compound suitable for use in non-linear optics

Optical elements having non-linear optical properties comprising a compound of the formula: ##STR1## wherein E is an electron donor

Non-linear optics

Optical elements having non-linear optical properties comprising a compound of the formula: ##STR1## wherein D is an electron donor

An optical element, such as a wave guide, having non-linear optical properties, suitable for use in optical devices in which it is desirable to alter the characteristics of the light, comprising a transparent or reflecting substrate having at least a partial superficial coating comprising alternating monolayers of a first non-linear optical (NLO) compound of the formula: ##STR1## wherein R is an non-hydrophilic aliphatic or cycloaliphatic group containing from 8 to 40 carbon atoms;

Optical element having non-linear optical properties

Optical elements comprising a non-centrosymmetric compound comprising an electron donor and an electron acceptor linked by a conjugated bridging group, in which the electron acceptor is a nitroso group, in which element the molecules of the compound are aligned so that the element has a net non-centrosymmetry, a method for their preparation, optical devices comprising such elements, and some of the compounds.

Non-linear optical device

(i) A compound of the formula: ##STR1## wherein R is H, a metal or a group containing a tetravalent N atom;

Optical element having non-linear optical properties including a

A compound of the formula: ##STR1## wherein E is an ethenyl group of the formula: ##STR2## in which X is H when Y is NO.sub.2 ;

Substituted pyrazoline having non-linear optical properties

Azo compound having one or two aliphatic or cycloaliphatic groups

1-phenyl-3-(2-nitroethenyl)pyrazoline and

A metal dithiene of the formula: ##STR1## wherein R.sup.1 is C.sub.3 to C.sub.20 alkyl;

Dithiene derivative

An infra-red absorbing phthalocyanine compound in which each of at least five of the peripheral carbon atoms in the 1, 4, 5, 8, 9, 12, 13 or 16 positions (the '3,6-positions') of the phthalocyanine nucleus, as shown in Formula I, is linked by an atom from Group VB or Group VIB of the Periodic Table, other than oxygen, to a carbon atom of an organic radical. In preferred compounds each of the eight 3,6-positions is linked by an atoms from Group VB or Group VIB, especially sulphur, selenium or nitrogen, to an organic radical. ##STR1##

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Rochdale, United Kingdom

Paul F Gordon