| 摘要 |
<p>Ultraviolet transmitting glasses exhibiting coefficients of thermal expansion between 46-52x10<-><7>/ DEG C and transmittances at a thickness of 1 mm of at least 80% at a wavelength of 254 nm which are essentially free of fluoride and consist essentially, in mole percent, of 60-70% SiO2, 16-20% B2O3, 1-8% Al2O3, 1-6% Li2O, 2.5-5% N2O, 0-3% K2O, and 0-1.25% Cl, wherein the mole ratio R2O:R2O3 is greater than 0.3, but less than 0.5.</p> |
