An alkali-free glass consisting essentially of from 60 to 74 mol % of SiO.sub.2, from 10 to 16 mol % of Al.sub.2 O.sub.3, from 10 to 12 mol % of B.sub.2 O.sub.3, the molar ratio of Al.sub.2 O.sub.3 /B.sub.2 O.sub.3 being from 1.0 to 1.5, from 0 to 5 mol % of MgO, from 0 to 5 mol % of CaO, from 0 to
An alkali-free glass consisting essentially of from 60 to 74 mol % of SiO.sub.2, from 10 to 16 mol % of Al.sub.2 O.sub.3, from 10 to 12 mol % of B.sub.2 O.sub.3, the molar ratio of Al.sub.2 O.sub.3 /B.sub.2 O.sub.3 being from 1.0 to 1.5, from 0 to 5 mol % of MgO, from 0 to 5 mol % of CaO, from 0 to 12 mol % of SrO, from 0 to 12 mol % of BaO, and from 6 to 12 mol % of SrO+BaO, which contains substantially no alkali metal oxide and has a strain point exceeding 650.degree. C. and an average thermal expansion coefficient of at most 40.times.10.sup.-7 /.degree.C. within a range of from 50.degree. to 300.degree. C., and of which the weight loss per unit area after immersion at 25.degree. C. for 20 minutes in a liquid prepared by mixing a 40 wt % ammonium fluoride aqueous solution and a 50 wt % hydrofluoric acid aqueous solution in a volume ratio of 9:1, is less than 0.60 mg/cm.sup.2, the weight loss per unit area after immersion at 95.degree. C. for 20 hours in 0.1N HCl, is less than 0.20 mg/cm.sup.2, and the liquidus temperature is at most a temperature at which the viscosity is 10.sup.4 poise.
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[ What is claimed is:] [1.] An alkali-free glass consisting essentially of from 60 to 68 mol % of SiO.sub.2, from 10 to 16 mol % of Al.sub.2 O.sub.3, from 10 to 12 mol % of B.sub.2 O.sub.3, said Al.sub.2 O.sub.3 and B.sub.2 O.sub.3 being present in a molar ratio of from 1.0 to 1.5, from 0 to 5 mol %
[ What is claimed is:] [1.] An alkali-free glass consisting essentially of from 60 to 68 mol % of SiO.sub.2, from 10 to 16 mol % of Al.sub.2 O.sub.3, from 10 to 12 mol % of B.sub.2 O.sub.3, said Al.sub.2 O.sub.3 and B.sub.2 O.sub.3 being present in a molar ratio of from 1.0 to 1.5, from 0 to 5 mol % of MgO, from 0 to 5 mol % of CaO, from 3 to 5 mol % of SrO, from 3 to 5 mol % of BaO, and from 6 to 8 mol % of SrO+BaO, which contains substantially no alkali metal oxide and has a strain point exceeding 650.degree. C. and an average thermal expansion coefficient of at most 40.times.10.sup.-7 /.degree.C. within a range of from 50.degree. to 300.degree. C., and of which the weight loss per unit area after immersion at 25.degree. C. for 20 minutes in a liquid prepared by mixing a 40 wt. % ammonium fluoride aqueous solution and a 50 wt. % hydrofluoric acid aqueous solution in a volume ratio of 9:1, is less than 0.56 mg/cm.sup.2, the weight loss per unit area after immersion at 95.degree. C. for 20 hours and 0.1 NHCl, is less than 0.20 mg/cm.sup.2 and the liquidus temperature is at most a temperature at which the viscosity is 10.sup.4 poise.
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