Patent ID: 6546753
Filing Date: 2003-04-15
Classification: C03C,G02F

Abstract:
A method of producing an alkali-free glass having a basic composition consisting essentially, by weight, of 40-70% SiO2, 6-25% Al2O3, 5-20% B2O3, 0-10% MgO, 4.5-15% CaO, 0-30% BaO, 0-10% SrO, and 0-10% ZnO, and containing substantially no alkali metal oxide, said method comprising the steps of preparing a glass batch of the basic composition, including an addition of a fining agent consisting of a combination of 0.05-3% Sb2O3, and at least one of 0.05-2% SnO2 and 0.01-2 wt % chloride in terms of Cl2, melting said glass batch into a glass melt, and forming said glass melt into a desired shape.