SOLARIZATION-RESISTANT BOROSILICATE GLASS, USE THEREOF IN PRODUCTION OF GLASS AND TUBE, AND USE THEREOF IN IRRADIATION UNIT

PROBLEM TO BE SOLVED: To provide a glass having higher solarization-resistance for a lamp exposed to ultraviolet rays, a light source, and an irradiation unit.SOLUTION: There is provided a borosilicate glass having high solarization resistance and a UV edge at a predetermined position, which has the following components: 65 to 85% of SiO, 7 to 20% of BO, 0 to 7% of AlO, 0 to 2% of LiO, 0 to 8% of NaO, 0 to 12% of KO, 0 to 5% of BaO, 0 to 2% of CaO, 0 to 2% of MgO, 0 to 2% of ZnO, 0.05 to 0.4% of TiO, 0.025 to 0.3% of MoOand 0.001 to 0.01% of VO(wt.% based on oxide). In addition, the total of the alkali metal oxide is 4.5 to 6.5%, the total of the alkaline earth metal oxide is 0 to 3%, and the borosilicate glass contains 0 to 0.3% of Cland 0 to 0.6% of Fas a clarifying agent.