Effects of Viscosity and Stress Level on Rates of Stress Release in Soda‐Lime, Potash‐Barium, and Borosilicate Glasses

Previous work has suggested that two concurrent mechanisms act to relieve stresses in soda‐lime commercial glasses in the viscosity range log 12 to log 14.5. The data were found to be best represented by a relation which indicated that the release of stress is the result of at least two distinct, but not necessarily independent, rate processes. The present paper shows stress release and viscosity data on two other types of glasses, namely, a potash‐barium glass and a borosilicate. The data show that all three types of glass can be represented by similar equations and that the release of stress in glasses is related to both equilibrium temperature viscosities and delayed elasticity within the annealing zone.