High uv - permeable borosilicate glasses with a reduced boron - content

摘要

The present invention relates to a borosilicate glass with a high uv - transmission, comprising or consisting of the following glass composition (in w -%, based on oxide):Sio₂ 65-72B₂O₃ 15-20Al₂O₃ 4-6Na₂O 0,5 - 3,5K₂O 1 - 3,5Li₂O 0,3 - 1,5Cao 0 - 1,0Bao 0,5 - 4Sum of li₂O + na.sub.2₂O + k₂O 3,8 - 5,5Sum of cao + bao 1 - 4, as well asone or several not oxidizing refining agent 0,1 - 2,0 andone or more reducing agent 0,05 - 0,5.The glass according to the invention is distinguished by an unexpectedly high uv - transmission, even though the b₂O₃-Content in comparison with the prior art, is lowered.