Modulus of Elasticity of Glass in Relation to Temperature*

The modulus of elasticity of a glass was determined at various temperatures by measuring the elongation of a glass fiber under load. The rate of decrease of modulus with temperature showed an abrupt change between 250°C and 300°C. It was considered that this phenomenon was connected with the increased rate of expansion which occurs in glasses near these temperatures. A description is given of an interferometric method of measuring the deflection of compressed specimens at temperatures up to the softening point of the glass.