METHOD OF DEPRESSING THE LIQUIDUS TEMPERATURE OF LANTHANUM ALUMINOGERMANATE GLASSES, AND THE GLASSES PRODUCED

摘要

The liquidus temperature of a lanthanum aluminogermanate glass is depressed by incorporating a selected additive in the glass batch. This produces a family of lanthanum aluminogermanate glasses composed essentially, in percent by weight on an oxide basis, of 25-50 percent GeO2, 1.5-25 percent Al2O3, 15-40 percent La2O3 and 2.5-45 percent of one or more oxides selected from the group Nb2O5, Ta2O5, SrO, BaO, PbO, and ZnO. These glasses have a substantial transmission for radiation in the five to six micron wavelength range, are hard and abrasion resistant, and have moderate coefficients of thermal expansion and good glassworking properties. They are particularly adapted to use as windows in infrared detection systems.