| 摘要 |
The invention relates to a glass which is transparent to UV radiation and which, for a thickness of 1 mm and the wavelength of 253.7 nm has a transmission of at least 75%, a linear coefficient of thermal expansion of 3.8x10-6 to 4.5x10-6K-1 in the temperature range from 20 DEG to 300 DEG C. and a hydrolytic resistance of <120 mu g of Na2O/g according to DIN 12 111. The new glass has the synthesis composition, calculated on an oxide basis, of -SiO2 64 to 66.5 percent by weight -B2O3 20 to 22.5 percent by weight -Al2O3 4 to 6 percent by weight -Li2O 0.4 to 1 percent by weight -Na2O 1.0 to 3.5 percent by weight -K2O 1.0 to 2.5 percent by weight -CaO 0.35 to 0.8 percent by weight -BaO 0.5 to 2.0 percent by weight -F- 0.5 to 2.0 percent by weight - SIGMA Li2O + Na2O + K2O 3.8 to 5.5 percent by weight - SIGMA CaO + BaO 1.0 to 2.5 percent by weight -one or more 0.2 to 2.0 percent by weight -non-oxidizing -refining agents -one or more 0.05 to 0.3 percent weight. -reducing agents -
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