| 摘要 |
A photochromic glass with the compsn. (wt.%, oxide basis) 52-58 SiO2, 16-21 B2O3, 6-9 Al2O3, 1.5-2.8 ZrO2, 2-3.5 Li2O, 0-2.5 Na2O, 4-8 K2O, 2-3.5 CaO and 1.2-2.5 TiO2, with 0.15-0.25 wt.% Ag, 0.06-0.13 wt.% Br, 0.25-0.40 wt.% Cl and 0.003-0.007 wt.% CuO as photochromic components and 2-10 ppm Au and up to 0.9% Er2O3 displays a pink hue in the darkened state, and bodies at 2 mm cross section have optical properties comprising: (i) luminous transmittance over 82% when undarkened, (ii) 20-32% and 35-55% darkened luminous transmittance after 15 min. exposure to actinic radiation at 25 deg. C and 40 deg. C respectively, (iii) a recovery of at least 30% in transmittance, to at least 50% transmittance, 5 min. after removal from exposure, and (iv) x and y trichromatic coordinates of 0.3500-0.3700 and 0.3250-0.3450 respectively. |
