| 摘要 |
This invention is directed to the production of glasses having a density of less than 3.26 g/cm3, a beta OH value less than 0.030 mm-1, and, in a thickness of 2 mm, a transmission of at least about 80% at a wavelength of 4.0 microns and at least about 50% at a wavelength of 5 microns, which have base compositions within the alkali metal oxide-CaO-Al2O3-GeO2-F and/or Cl field consisting essentially, expressed in terms of weight percent on the oxide basis, of -GeO2 36-55 -Al2O3 18-31 -CaO 10-25 -Li2O 0-5 -K2O and/or Na2O and/or Li2O 7-20 -Al2O3 + 1.5 (K2O and/or Na2O and/or Li2O) >/=40 -F and/or Cl 0.1-4. -
|
