Elastic Moduli of Glasses at Elevated Temperatures by a Dynamic Method

The elastic constants of thirteen glasses were measured by a dynamic method at elevated temperatures. Both Young's modulus and the shear modulus were determined and from these Pois‐son's ratio was calculated as a function of temperature. Fused silica, Vycor‐brand glass, and Pyrex‐brand glass had positive temperature coefficients of elastic moduli, whereas all the other glasses showed negative coefficients. Poisson's ratio was found to rise with temperature in all thirteen glasses. This is interpreted as an indication of an approach to the liquid state.