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, have been investigated by dielectric relaxation spectroscopy employing two different experimental techniques, i.e., complex impedance spectroscopy (CIS) and the thermally stimulated current (TSC) technique. The results of these two dielectric spectroscopies can be fruitfully analyzed in terms of distribution functions of relaxation times and favorably compared. The dielectric 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 two or three types of network sites. The activation energies for cation detrapping and for ionic mobility were also evaluated.