Development of an Inorganic Phototropic System for Flashblindness Protection

摘要

The report presents the details of a study made to determine the feasibility of using films containing one or more heteropoly acids for possible protection against flashblindness. Phosphomolybdic, phosphovanadomolybdic, phosphotungstic, silicotungstic, and silicomolybdic acids were evaluated. Methods for the preparation and purification of heteropoly acids in general are given. Also given are details for the preparation and purification of specific compounds: potassium-arseno-12-molybdate, phospho-18-molybdic acid, arseno-12-molybdic acid, purpureophospho-12-vanadic acid, and borotungstic acid. Films for evaluating the photochromic response were prepared by centrifugally spinning a thin film of acid-resin solution on a polyester substrate and evaporating the solvent. Photochromic response and capabilities were determined by (1) exposing the films to a xenon flash, an ultraviolet lamp, and a xenon-mercury arc; and (2) measuring the optical transmission or density before and after exposure. The response of several films, particularly phosphomolybdic acid in polyvinyl acetate (which changed from an optical density of 0.07 to a density of 3.4), indicates that further research in this area is warranted. Also, since several of the films were somewhat heat sensitive, a study of different resins in indicated. (Author)