Infrared spectroscopic study of mixed-alkali effect in borate glasses

Abstract

Infrared spectra of mixed-alkali diborate glasses, $(Li, Na)_20.2B_2O_3$ and $(Li, K)_20.2B_2O_3$, have been investigated. B-O stretching and B-O-B bending frequencies exhibit nonlinear shifts which can be described as a mild mixed-alkali effect. Both shifts and nonlinear variations of frequencies may be explained on the basis of alteration of the structure of the diborate groups in the presence of $Li^+$ ions