To provide a process for producing and
alkali free glass for effectively suppressing bubbles, and an
alkali free glass produced by the process, which is suitable as a glass substrate for
flat panel displays and has few bubbles.A process for producing an
alkali free glass containing substantially no
alkali metal oxide, which comprises melting a glass starting material having a
matrix composition of the following composition, and subjecting the
molten glass to a treatment process of removing bubbles under reduced pressure, stirring or transferring under a condition where the
molten glass is in contact with a
platinum member, wherein the starting material is prepared so as to contain SnO2 in an amount of from 0.01 to 2.0% per 100% of the total amount of the above
matrix composition; the starting material is melted under heating at from 1,500 to 1,650° C.; then bubbles contained in the
molten glass are permitted to rise to the surface of the molten glass, together with
oxygen bubbles generated by a reduction reaction in which SnO2 in the molten glass is reduced to SnO; and in the above treatment process, the
oxygen bubbles generated at the interface between the molten glass and the
platinum member are permitted to be absorbed by an oxidation reaction in which SnO is oxidized to SnO2, under a condition where the molten glass is from 1,300 to 1,500° C.Composition as represented by the
mass percentage:SiO258.4 to 66.0%,Al2O315.3 to 22.0%,B2O3 5.0 to 12.0%,MgO 0 to 6.5%,CaO 0 to 7.0%,SrO 4 to 12.5%,BaO 0 to 2.0%,MgO + CaO + SrO + BaO 9.0 to 18.0%.