Local structural disorder and mobility of Ag+ ions in silver borate glasses containing alpha-AgI stabilised at room temperature

EXAFS temperature dependent measurements at the I K-edge have been done on AgI rich silver borate glasses containing crystallites of AgI stabilised in the a-phase at room temperature, as obtained by fast roller quenching. Data analysis was performed in the cumulant expansion approximation, to distinguish between structural and vibrational disorder, and the first shell I-Ag radial distribution functions were determined. The thermal behaviour of this composite will be compared to that of a homogeneous AgI-AgO-B2O3 glassy systems. The relation between temperature dependent local disorder and mobility of Ag+ ions in both systems will be discussed also in the light of previous results obtained by x-ray diffraction, conductivity and heat capacity measurements