X-ray photoelectron spectroscopy can be applied to the study of bonding properties of metal oxides in silicate glasses and to the analysis of water-leached glass surfaces. The addition of CaO to Na2O-2SiO2 results in a decrease in the number of bridging oxygen atoms in the glass matrix as monitored by oxygen 1s peak intensities. In sodium disilicate glasses containing dissolved uranium, significantly different leaching behavior can occur, depending on the oxidation state of the uraniumions.