use of a resin of polyvinyl chloride or copolymers to block the colored form of indolinischen or benzothiazolischen spiropyranen and types of reproduction with photochromer composition

摘要

A photochromic spiropyran compound is uniformly dispersed in a vinyl chloride homopolymer or copolymer resin binder. The resulting photosensitive composition provides an image which is highly stable against exposure to light, darkness, and heat when the composition is exposed to a light source emitting radiation of wavelength which includes the absorption band of the spiropyran compound. By incorporating polyvinylidene chloride in the photosensitive composition a positive reproduction of an original can be obtained by a dry photographic process in which the photosensitive composition is first irradiated through an original to form a stable pale yellow complex between hydrochloric acid produced by decomposition of the polyvinylidene chloride and the merocyanine produced from the photoisomerization of the spiropyran compound and thereafter again irradiating the entire photosensitive composition to form a stable colored complex in the areas which were not originally exposed which correspond to the opaque areas of the original. A photothermal development process is accomplished with a composition which includes the photochromic spiropyran compound, the polyvinyl chloride binder and at least one additional material selected from hydrolyzed polyvinyl alcohol, hydroxyethyl cellulose, or carboxymethyl cellulose.