Patent ID: 6063718
Filing Date: 2000-05-16
Classification: C03C,H01J

Abstract:
A glass composition intended for the manufacture of thermally stable substrates or panes, characterized in that it comprises the following constituents in the following proportions by weight: SiO.sub.2 55-60% Al.sub.2 O.sub.3 1-4% ZrO.sub.2 6-9% B.sub.2 O.sub.3 0-1% Na.sub.2 O 3-5% K.sub.2 O 5-9% MgO 1-6% CaO 7-11% SrO 6-10% BaO 0-1% SO.sub.3 0.005-0.15%  with the relationships:Na.sub.2 O+K.sub.2 O.gtoreq.10%.ltoreq.15%MgO+CaO+SrO+BaO.gtoreq.15%.ltoreq.25%K.sub.2 O/Na.sub.2 O.gtoreq.1.5Al.sub.2 O.sub.3 +ZrO.sub.2 .gtoreq.9%.ltoreq.15%, the said composition having a strain point which is in excess of 600.degree. C.