Polaroid Corporation

Anthony J Puttick

Stephen J Telfer

Jurgen M Grasshoff

John L Marshall

Mark R Mischke

Lloyd D Taylor

Roger A Boggs

Richard A Minns

Stephen G Stroud

Michael J Zuraw

James R Bartels-Keith

David P Waller

Kenneth C Waterman

Socorro M Ramos

Robert P Short

Donald A McGowan

Peter K Chu

John W Lee

Serajul Haque

Paulina P Garcia

Thomas K Spencer

Nancy M Sofen

James R Bartels-Keith, Deceased

Squarylium compounds, and processes and intermediates for the synthesis of these compounds

Dyes comprising an inner salt of a compound of the formula:

Benzpyrylium squarylium and croconylium dyes, and processes for their

Squarylium compounds of the formula: ##STR1## wherein Q.sup.1 and Q.sup.2 are each independently a pyrylium, thiopyrylium, selenopyrylium, benzpyrylium, benzthiopyrylium or benzselenopyrylium nucleus, and R.sup.1 and R.sup.2 are each independently an aliphatic or cycloaliphatic group, can be prepared by reacting a squaric acid derivative of the formula: ##STR2## with a compound of the formula Q.sup.2 CH.sub.2 R.sup.2 in the presence of a base.

Squarylium compounds, and processes and intermediates for the synthesis

Certain squaric acid derivatives are useful for the thermochemical generation of acid. The squaric acid derivatives may be used in imaging media in conjunction with acid-sensitive materials which undergo a color change when contacted by the acid generated from the squaric acid derivatives. Preferably, the acid-sensitive materials undergo an irreversible color change, so that the image can be fixed by neutralizing all the acid generated with excess base, thereby preventing further color change in the image during long term storage.

Process for thermochemical generation of acid and for thermal imaging,

Acid can be generated by exposing a mixture of a superacid precursor and a dye to actinic radiation of a first wavelength which does not, in the absence of the dye, cause decomposition of the superacid precursor to form the corresponding superacid, thereby causing absorption of the actinic radiation and decomposition of part of the superacid precursor, with formation of a protonated product derived from the dye, then irradiating the mixture with actinic radiation of a second wavelength, thereby causing decomposition of part of the remaining superacid precursor, with formation of unbuffered superacid. Preferably, following these irradiations, the imaging medium is heated while the superacid is admixed with a secondary acid generator capable of being thermally decomposed to form a second acid, the thermal decomposition of the secondary acid generator being catalyzed by the presence of the superacid. The acid generation process may be used for imaging by bringing the superacid or second acid into contact with an acid-sensitive material which changes color on contact with acid, or the superacid may be used to trigger polymerization, depolymerization or other reactions.

Process for generation of unbuffered super-acid and for imaging

Acid can be generated by exposing a superacid precursor to actinic radiation effective to generate superacid from the superacid precursor and heating the superacid in admixture with a secondary acid generator capable of undergoing thermal decomposition to produce a secondary acid. The superacid catalyzes decomposition of the secondary acid generator, thus increasing the quantity of strong acid present in the medium. The resultant secondary acid can be used to effect a color change in an acid-sensitive material, so providing an imaging process.

Process for generation of acid and for imaging, and imaging medium for

Process for thermochemical generation of acid and for thermal imaging

Imaging medium

Process for thermochemical generation of squaric acid and for thermal

There are described novel photographic products and processes which utilize compounds which release a photographic reagent in the presence of alkali. The compounds include an imidazole blocking group and cleave in alkali to release the photographic reagent. Also described are novel compounds.

Photographic reagent tetrazoles

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Arlington, MA, United States of America

Anthony J Puttick