The use of XPS for characterisation of glass fibre coatings

We present the results of an investigation of the use of X-ray photoelectro n spectroscopy (XPS) as a tool for the rapid characterisation of glass fibr e coatings. XPS data have been obtained from a wide range of commercial and experimental glass fibres using three different XPS instruments. By develo ping a protocol to plot ratios of appropriate atom concentrations, XPS anal ysis has been shown to give new insights into the in situ nature of the coa ting on glass. We show how these plots of atom ratios can be used to estima te the surface coverage of the coating on the glass fibres and obtain infor mation on the chemical composition of the coating. Relationships between th e XPS data and coated glass fibre parameters are clarified with the aid of a patchy overlayer model. We discuss the use of the XPS Si peak as a glass reference atom in different coverage regimes, and the effect of different X PS detector exit angles. In comparing data from three XPS instruments excel lent correlation was obtained after correcting for differences in spectrome ter sensitivity factors. (C) 1999 Elsevier Science Ltd. All rights reserved .