PROCESS FOR PRODUCING GLASS

摘要

A process for producing a glass, in which the synergic effect of vacuum deaeration (vacuum clarification) and clarificant is enhanced by regulation of glass composition, thereby obtaining a high clarification effect. There is provided a process for producing a glass containing substantially none of sodium oxide, comprising melting a raw material into a glass melt and clarifying the glass melt in a vacuum atmosphere. As the raw material, use is made of one wherein the content of Cl is in the range of 0.02 to 5 mass% mixed so that in the glass, the ratio of the total mass of MgO and CaO to the total mass of MgO, CaO, SrO and BaO is = 0.20. The clarification potency of Cl especially with respect to the glass melt satisfying the above total mass ratio is strikingly enhanced in vacuum as different from those of other clarificants.