Time Factors in the Breaking of Toughened Glass

Abstract

RECENTLY there has been much interest in the relationship between rates of stressing and strength properties of glass, and several hypotheses and relations have been put forward in connexion with the quantitative phenomena concerned^1-5. In one of these¹, it is suggested that the decrease of the broaking stress with increase in duration of loading should be slower with toughened glass than with sheet. However, the same conclusion follows from the quantitative formulation⁶ of the commonly accepted view of the nature of toughened glass, namely, bending strength of toughened glass = bending strength of sheet glass + increase due to toughening process=ƒ_(t) + K.