J. Phys. IV France 7 (1997) C2-1169-C2-1170
EXAFS Study of Silver and Rubidium Environments in Silicate GlassesM. Dubiel1, S. Brunsch1, I. Arcon2 and R. Frahm3
1 University of Halle, Friedemann-Bachplatz 6, 06108 Halle, Germany
2 J. Stefan Institute and Department of Physics, University of Ljubljana, Jamova 39, 61111 Ljubljana, Slovenia
3 HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
In order to study local order around Ag and Rb ions in ion-exchanged glasses EXAFS experiments were performed after thermal annealings at different temperatures below and above the glass transformation temperature. By means of Ag K-edge spectra three coordination spheres could be discussed. Whereas the two Ag-O distances remain unchanged during thermal treatments the Ag-Ag correlation exhibits the influence of the transformation of Ag ions to crystalline precipitations at elevated temperatures. The Rb K-edge spectra present anomalous oscillations which can be ascribed to multi-electron excitations [ls3d]. In order to evaluate the main EXAFS signal, these features were subtracted using absorption data of gaseous rubidium. The Fourier transforms display similar Rb-O bond lengths within the first sphere for both the ion-exchanged soda-lime and the disilicate glasses while relaxation phenomena modify the second oxygen sphere towards the disilicate structure.
© EDP Sciences 1997