Fracture Toughness of Fused SiO ₂ and Float Glass at Elevated Temperatures

Abstract

The fracture toughnesses of fused SiO 2 and float glass were measured at high temperatures. In both glasses, low‐temperature regions of elastic fracture were identified and correlated with the elastic moduli and their temperature dependence. A viscous flow contribution to the fracture toughness was identified in the fused SiO 2 at T >800°C. Similar indications of viscous flow were also noted in the float glass, although at much lower temperatures.