Relaxation time and viscosity of fused silica glass at room temperature
Cases of long-term deformation of fused silica glass at room temperature attributed to the action of gravity have been reported. Further experimental investigations now provide evidence of time-dependent viscous behavior, with a time constant of the order of 10 years. Data relating to a pair of fused silica reference plates are presented, showing the overall deformation occurred over the years; considerations on the pertaining viscosity with aging are also given. An account of the observed relaxation process in terms of the Kelvin-Voigt model for linear viscoelasticity is provided.
KeywordsFuse Silica Linear Viscoelasticity Knoop Hardness Fuse Silica Glass Absolute Planarity
- 7.B.S. Fritz, Opt. Eng. 33, 379 (1984).Google Scholar
- 11.Guide to the Expression of Uncertainty in Measurement (ISO - International Organization for Standardization, Geneva, 1993).Google Scholar
- 12.B. Mysen, P. Richet, Silicate Glasses and Melts (Elsevier, Amsterdam, 2005) p. 134Google Scholar
- 16.L. Landau, E. Lifchitz, Théorie de l’Élasticité (MIR, Moscou, 1967) pp. 201-203Google Scholar
- 17.H.A. Barnes, J.F. Hutton, K. Walters, An Introduction to Rheology (Elsevier, Amsterdam, 1989) pp. 39-43Google Scholar