RELIEF OF RESIDUAL STRESSES IN GLASSES BY APPLICATION OF ULTRASONIC ENERGY.

Abstract

An experimental investigation was carried out for relieving the residual stresses in glass specimens by the application of ultrasonic energy. Highly strained specimens of potassium lead, borosilicate, and soda lime glasses of dimensions 2 multiplied by 1. 5 multiplied by 0. 15 inch were used. The stress pattern developed was approximately uniaxial. The specimens were coupled to the transducer and heated to a fixed temperature in an electric oven during application of ultrasonic energy. Partial relief occurred after application of the ultrasonic energy for one hour at temperatures in the range 280 to 350 degree C, the maximum relief effect being obtained at a temperature of 315 degree C. A comparison of the results obtained for each type of glass showed that the amount of stress relief increases with increase of oxides.