We present an x-ray absorption spectroscopy study at the CuKedge on Cu-doped soda-lime and BK7 glass waveguides obtained by ion exchange under various preparation conditions. The total electron yield and x-ray fluorescence yield collection modes were used to evidence the chemical behavior of surfacial and deep Cu ions. In all the samples copper is found preferentially asCu+throughout the whole exchanged region. The first coordination shell is formed by two to three oxygen atoms at 1.86 Å, much shorter than the Na–O bond (2.3 Å) in soda-lime glasses. ©1997 American Institute of Physics.