Influence of Network Structure on Thermo-Viscoelastic Property for Optical Glass

In this study, unidirectional compression creep tests were performed on seven types of commercial optical glasses with different chemical compositions to investigate the effect of chemical composition or network structure on stress relaxation behavior. As a result of comparing stress relaxation rates obtained by dividing the shear relaxation modulus by the shear instantaneous modulus, they showed almost the same shape on the logarithmic time axis. In other words, it was clarified that the chemical composition has almost no effect on the stress relaxation behavior, at least in the glasses used in this study. On the other hand, it was confirmed that the difference in chemical composition affects the relaxation time, and the relaxation time of the chain structure glass tends to be delayed compared to that of the three-dimensional network structure glass. Furthermore, the activation energy of viscous flow obtained by approximating the shift factor also tended to be slightly lower in the chain structure glass. ©2022 The Society of Materials Science, Japan.