摘要 |
A method for shifting the absorption peak wavelength in the wavelength range 900-1600 nm of an infrared radiation absorbing glass from less than 1100 nm to 1100 nm or longer without substantially changing the tint of the glass, comprising the step of irradiating with ultraviolet light of 400 nm or shorter at an energy density of 1.0x106 J/m2/hr or more to increase the content of FeO in the irradiated glass by reducing Fe (III) to Fe (II), the ultraviolet light irradiated glass thereby comprising 0.02 wt. % or more FeO in terms of Fe2O3. The glass to be irradiated comprises, in % by weight: 65 to 80% SiO2, 0 to 5% Al2O3, 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na2O, 0 to 5% K2O, 5 to 15% MgO+CaO, 10 to 20% Na2O+K2O, and 0 to 5% B2O3; 0.02% or more total iron oxide (T-Fe2O3) in terms of Fe2O3, 0 to 2.0% CeO2, 0 to 1.0% TiO2, 0 to 0.005% CoO, and 0 to 0.005% Se.
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