摘要 |
<p>This invention is directed to the production of photochromic glass microsheet which is particularly useful in the fabrication of transparent glass-plastic composite lenses. In such lenses, the photochromic microsheet will either be buried within the plastic or will act as a surface layer thereon. The microsheet consists essentially, in weight percent on the oxide basis as calculated from the batch, of 54-66% SiO2, 7-15% Al2O3, 10-30% B2O3, 3-15% Na2O, 0.4-1.5% PbO, 0.2-0.5% Br, 0.5-1.2% Cl, 0.2-0.5% F, 0.008-0.03% CuO, and >0.03%-1% Ag.</p> |