LOCAL ATOMIC ENVIRONMENT OF CU IONS IN ION-EXCHANGED SILICATE GLASS WAVE-GUIDES - AN X-RAY-ABSORPTION SPECTROSCOPY STUDY

We present an x-ray absorption spectroscopy study at the Cu K edge on Cu-doped soda-lime and BK7 glass waveguides obtained by ion exchange u nder various preparation conditions. The total electron yield and x-ra y fluorescence yield collection modes were used to evidence the chemic al behavior of surfacial and deep Cu ions. In all the samples copper i s found preferentially as Cu+ throughout the whole exchanged region. T he first coordination shell is formed by two to three oxygen atoms at 1.86 Angstrom, much shorter than the Na-O bond (2.3 Angstrom) in soda- lime glasses. (C) 1997 American Institute of Physics.