Abstract: An electric arc discharge lamp has an arc discharge light source which emits both visible light radiation and UV radiation enclosed within a borosilicate, outer glass envelope. The envelope has a transmission of greater than 90% at a wavelength of 425 nm and a transmission of not more than 40% of UV radiation at 320 nm; 8% of UV radiation at 300 nm; and 0.5% of UV radiation at 290 nm. The borosilicate glass comprises, in weight percent: from about 3.89% Na.sub.2 O; about 1.5% K.sub.2 O; from 0.0% to about 0.15% Li.sub.2 O; about 17% B.sub.2 O.sub.3 ; about 1.4% Al.sub.2 O.sub.3 ; about 0.6% CaO; about 0.35% MgO; about 0.13% Fe.sub.2 O.sub.3 ; and the balance SiO.sub.2.

Abstract: An electric arc discharge lamp having an arc discharge light source which emits both visible light radiation and UV radiation enclosed within an anti-solarization borosilicate glass envelope which is lead and arsenic free and having a transmission of greater than 90% at a wave length of 425 nm and a transmission of not more than 40% of said UV radiation at 320 nm; 8% of said UV radiation at 300 nm; and 0.5% of said UV radiation at 290 nm; said borosilicate glass comprising, in weight percent: from about 3.89% Na.sub.2 O; about 1.5% K.sub.2 O; about 0.15% Li.sub.2 O; about 17% B.sub.2 O.sub.3 ; about 1.4% Al.sub.2 O.sub.3 ; about 0.6% CaO; about 0.35% MgO; about 0.15% CeO.sub.2 ; from about 0.075% to about 0.30% SnO.sub.2 ; and the balance SiO.sub.2. Also, a glass having the above composition.