Dielectric relaxation and far-infrared spectroscopic study of cation-site interactions in oxide glasses

Alkali triborate glasses M2O . 3B(2)O(3), With M = Li, Na, K, Rb, and Cs, h ave been investigated by dielectric relaxation spectroscopy employing two d ifferent experimental techniques, i.e., complex impedance spectroscopy (CIS ) and the thermally stimulated current (TSC) technique. The results of thes e two dielectric spectroscopies can be fruitfully analyzed in terms of dist ribution functions of relaxation times and favorably compared. The dielectr ic results are discussed by analyzing the far-infrared absorption profiles due to the localized metal cation sire vibrations. Both dielectric and far- infrared spectroscopies show that metal cations are embedded in at least tw o or three types of network sites. The activation energies for cation detra pping and for ionic mobility were also evaluated.