Possible differences between the surface and bulk structure of glasses

Changes in cation co-ordination at glass surfaces (indicating an increase of the oxygen-to-cation ratio within the topmost superficial layers) are evidenced by comparing data acquired by spectroscopic techniques of different excitation depth. Based on these experimental results, a theoretical model is developed that predicts structural discrepancies between surface and bulk structure. Such reconstructed surfaces are of great importance for all kind of surface-related crystallization phenomena.