Nonlinear Maxwell behavior of sodium silicate glass in the surroundings of glass transition temperature

Abstract

Presented are results from uniaxial cylinder upsetting tests of sodium silicate glass at different constant deformation rates each combined with relaxation experiments in the temperature range 480 to 580°C. Due to the complete stress relaxation to final load zero (vanished carrying capacity) also below glass transition temperature Tg, it follows Maxwell behavior in principle. But the rheological analyses of loading and unloading experiments together show that only nonlinear Maxwell model approaches can adequately describe the deformation behavior of the glass in the surroundings of Tg.