Oxygen diffusion in silica glass prepared by the sol–gel method

Abstract

The oxygen diffusion constants for SiO 2 coatings, prepared by the sol–gel method, were determined from Auger depth profile and Raman measurements. To do that, the coatings were deposited on copper substrates, and isothermally treated at various temperatures in air. The oxygen diffusion through the glass coating formed an oxide layer at the copper/SiO 2 interface. The treatment times, at a given temperature were maintained until the minimum thickness of the copper oxide layer formed at the copper/SiO 2 interface was detectable by Raman spectroscopy. This oxide layer thickness was determined from Auger depth profile measurements. The room temperature values for the diffusion constant and the activation energy were, 2.2×10 −15 cm 2/s and 0.5 eV, respectively.