M. Koide et al., DELAYED ELASTICITY AND VISCOSITY OF SILICATE-GLASSES BELOW THE GLASS-TRANSITION TEMPERATURE, Thermochimica acta, 283, 1996, pp. 345-351
The viscosity of pre-annealed lead-silicate glass was studied below th
e glass transition temperature using the fiber-bending method. The vis
cosities were determined under conditions of loading and unloading. Th
e delayed elasticity and its effect on the viscosity were also investi
gated. In the case of equal loading and unloading times, the viscosity
was the same for the loading and unloading processes and the delayed
elasticity was larger within shorter periods and smaller for longer on
es. In addition, the time necessary for the recovery of the delayed el
asticity increases with increasing loading time.