Patent ID: 6630420
Filing Date: 2003-10-07
Classification: C03C

Abstract:
A glass having a high zirconium oxide content and a composition consisting of, in percent by weight based on oxide content:SiO254 to 72Al2O30.5 to 7â€‚â€‰ZrO210 to 20B2O3â€‚0 to <5CaOâ€‚3 to 11MgOâ€‚0 to 10SrO0 to 8BaOâ€‚0 to 10CaO + MgO + SrO + BaO>5 to 24Na2Oâ€‚2 to <8K2O0 to 5Na2O + K2Oâ€‚2 to <8La2O30 to 5TiO20 to 4and optionally at least one fining agent in an amount sufficient for fining; wherein either said TiO2 is present in amounts greater than 0.1 percent by weight or said La2O3 is present in amounts greater than 0.6 percent by weight.