X-RAY PHOTOELECTRON-SPECTROSCOPY STUDY OF COPPER-SODIUM SILICATE GLASS SURFACES

Copper oxide-containing, sodium silicate glasses with composition (0.7 0-x)SiO2-0.30Na(2)O-xCuO (x in the range 0-0.2), were prepared by conv entional melting and casting. The surface structure has been investiga ted by X-ray photoelectron spectroscopy. Evidence for the presence of copper in the Cu+ state for glasses with x less than or equal to 0.14, and for both oxidation states (Cu+ and Cu2+) in the glass where x = 0 .18, has been obtained from the ''shake up'' satellite structure of th e Cu 2p core level spectra. A deconvolution procedure has been underta ken to determine quantitatively the [Cu2+]/[Cu-total] ratio. The non-b ridging oxygen content, obtained from the deconvolution of the O 1s co re level spectra, increases with increasing copper oxide content indic ating that copper acts as a network modifier. The O 1s spectra were mo delled in such a way as to separate the contributions from SiOCu and S iONa to the non-bridging oxygen signal. (C) 1997 Elsevier Science B.V.