Patent ID: 11760684

Abstract:
The present invention provides a glass composition not requiring a large quantity of rare earth material, producible by a common apparatus for producing a glass, having a high Young's modulus and a large crack initiation load, and suitable for glass fibers etc. A glass composition according to the present invention contains, in mol %: 50 to 65% SiO2; 7.5 to 26% Al2O3; 15 to 30% MgO; 0 to 8% CaO; 0 to 3% B2O3; 0 to 3% Li2O; and 0 to 0.2% Na2O. In this glass composition, a total content of MgO and CaO is in a range of 18 to 35 mol %, and a mol ratio calculated by Al2O3/(MgO+CaO) is less than 1.