Dark bronze glass with improved UV and IR absorption and nitrate-free manufacturing process therefor

Abstract

The invention is a dark bronze soda-lime-silica glass composition having excellent ultra violet and infra red absorbing ability. The colorants of the glass composition consist essentially of: greater than 0.5% total iron oxide as Fe.sub.2 O.sub.3 with a maximum of 1.5% Fe.sub.2 O.sub.3, wherein the redox ratio of FeO/total Fe as Fe.sub.2 O.sub.3 is less than 0.26; 0.10 to 1.00 wt. % manganese compound as MnO.sub.2 ; 0.0005 to 0.004 wt. % selenium as Se; up to 0.016 wt. % cobalt oxide as Co; 0-1.0 wt. % TiO.sub.2, the glass composition having, at 4.0 mm. thickness: 570-585 dominant wavelength, 5-30% purity of excitation, 20 to 65% light transmittance using Illuminant A (LTA), less than 35% ultra violet transmittance measured over 300-400 nm, and less than 46% infra red transmittance measured over 760-2120 nm. At 20-50% LTA, the excitation purity is 7-30%, while above 50% LTA, the excitation purity is 5-20%. This glass is particularly useful for architectural applications.

Dependencies are inferred from the claim text.