Structural investigation of lithium bismuth borate glasses through Raman and infrared spectroscopies

Abstract

AbstractThe structure of lithium bismuth borate glasses in the compositional series xBi2O3–25Li2O–(75 − x) B2O3 was studied with the use of Raman and infrared (IR) spectroscopies. Transparent glasses formed between x = 0 and 55, whereas glass–ceramics formed between x = 60 and 75 mol% Bi2O3. Structural investigation on the borate network showed that the glasses were undermodified at high Bi2O3 compositions with metaborate, pyroborate, and orthoborate triangles and tetrahedra being present past the stoichiometric orthoborate compositions (O/B = 3). Bi2O3 was found to participate in the glass as both a network former and modifier, as observed in the Raman and IR spectra. Optical absorption spectra of the glasses show a redshift of the absorption edge with increased Bi2O3. Optical, thermal, and physical properties of the glasses were examined and correlated to the structural evolution.