abstract |
A fixed tint, photochromic glasses and sunglass lenses produced therefrom. The glasses have R2O-Al2O3-B2O3-SiO2 base compositions, contain silver chloride and bromide contents as photochromic constituents and 0.27-0.38 % and 0.035-0.060 %, both by weight percent, as glass colorants, the NiO:Co3O4 ratio being at least 6:1. |