New photochromic materials for visible range

摘要

Abstract: A novel light-sensitive material has been developed to realize the reversible (as in usual photochromic materials) and irreversible (as in photographic systems) recording of information. The substituted indolinospirobenzopyran was used as a light-sensitive component in polystyrene matrix. At the low exposures in the UV range of spectrum the light-sensitive material works as an usual photochromic one, at large exposure it functions as a photographic layer and in the latter case the irreversible image is registered. The image can be devisualized by heating of the exposed material and restored many times by the flood UV irradiation of the material. The kinetic scheme of photoreaction proceeding in the material is discussed. Besides, in this work new recording materials and process of photochemical image registration were elaborated. Entirely hidden image recorded on this material is visualized in polarized light. The image is stable to the temperature, chemical, mechanical influences. The process is a method of protecting documents, financial securities and products from forgery by incorporation of a `label authenticity' onto the product to be protected. The label of authenticity is obtained by exposing the light-sensitive polymer layer to UV radiation, as a result of which its optical properties change.!5