Influence of swelling stresses on the shift of Raman vibration peaks

Abstract

An interesting effect in silica glass is the shift of IR- and Raman-peaks under externally applied stresses. A first interpretation of the influence of stress on the IR frequency was made possible by its influence on the bond angles, as had been shown very early by Galeener [1]. In this interpretation, the stress effect is assumed as a consequence of a change of the bond angles due to the stresses. In [2] we could show that the angle stretching is not the only effect that influences the position of the frequency of IR lines. For our computations we used the Lennard-Jones potential and could show that a tensile stress must result in a decrease of the frequency. In the present report, we will show in which way also the water concentra tion in the surface region can affect the measurements via volume swelling due to the hydroxyl generation by the silica/water reaction.