Structural investigation of lithium bismuth borate glasses through Raman and infrared spectroscopies
Elizabeth M. Tsekrekas, Sophia J. Carretto, Doris Möncke, Alexis G. Clare
Abstract
Abstract The structure of lithium bismuth borate glasses in the compositional series x Bi 2 O 3 –25Li 2 O–(75 − x ) B 2 O 3 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% Bi 2 O 3 . Structural investigation on the borate network showed that the glasses were undermodified at high Bi 2 O 3 compositions with metaborate, pyroborate, and orthoborate triangles and tetrahedra being present past the stoichiometric orthoborate compositions (O/B = 3). Bi 2 O 3 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 Bi 2 O 3 . Optical, thermal, and physical properties of the glasses were examined and correlated to the structural evolution.