AN OXYGEN XAFS STUDY OF SODIUM DISILICATE GLASS SURFACES

Oxygen K-edge X-ray absorption fine structure (XAFS) spectroscopy has been employed to study the atomic structure near the surface of powder ed and polished sodium disilicate glass. In the absence of lubricants, grinding in air produces substantial quantities of sodium carbonate. This is also present for surfaces polished in water but vanishes for s urfaces polished in oil. Results are interpreted in terms of the modif ied random network (MRN) model in which microsegregated alkalis decora te newly created glass surfaces, reacting variously with oxygen, carbo n dioxide and water.