Method of providing a phototropic layer on a carrier

Claim 1

That method of rendering at least one major surface of an optical or ophthalmic organic or inorganic lens phototropic comprised of the steps: (a) preparing a clean lens surface to be treated; (b) preparing a liquid temporary-carrier of a stable solution of a mixture of silicon containing metal organic compound and a metal organic compound containing boron and phosphorous with nitric acid and copper nitrate and silver nitrate, said mixture being pyrolyzable to form a glassy matrix comprising SiO 2 , P 2 O 5 , and B 2 O 3 and mixtures thereof for the phototropic material to be placed on the lens; (c) exposing the said clean lens surface to said temporary-carrier and phototropic-layer-forming material under conditions capable of depositing a thin, hard, scratch-resistant glass layer over said lens surface, said layer having substantially uniformly distributed therewith color centers which, when subjected to ultraviolet or shortwave visible light exhibit reversible absorption thereof.