Photochromic glass contg. silver - as a simple or complex phosphate to improve stability of the silver

摘要

Photochromic glass is prepd. by introducing silver into a glass compsn. in the form of a cpd. comprising Ag,P and O, esp. Ag3PO4, Ag2HPO4 or a double or multiple silver phosphate such as (NaAg)(PO3)2. The components of the glass compsn. and the silver phosphate are prepd. in the form of finely divided powders and mixed homogeneously. The mixt. is melted at 1200-1600 degrees C, cooled, then reheated to 500 degrees C. Halide(s) may be added to the compsn. so that during the formation of the glass AgCl may be formed by pptn. Minor inclusions of metallic silver in the glass are eliminated.