Structural investigation of lithium borate glasses by Raman spectroscopy: Quantitative evaluation of structural units and its correlation with density

Abstract

Lithium borate glass is a widely studied system, mainly due to its good ionic conductivity, thermal conductivity and thermoluminescence properties. The properties of lithium borate glass are determined by its structure, and the change of microstructure unit has great influence on its properties. In this work, the xLi2O⋅(1-x) B2O3 (0.1 ≤ x ≤ 0.48) glass was studied by Raman spectroscopy combined with peaks fitting and density analysis. Through quantitative analysis of Raman spectrum, the change in trend of each structural unit as well as the change of the tetracoordinated boron content (N4) were obtained with the increase of Li2O content. Especially, a more detailed assignment and general transformation mechanism of structural units were presented, and the common inflection points of properties (mass density, molar volume, etc.) and structural units content changes were found. The correlation between the properties (mass density, atomic density and molar volume) and the basic structural units (BØ3, BØ2O− and BØ4−) of the lithium borate glass was established by the genetic function approximation algorithm (GFA). The study on the structural units in xLi2O⋅(1-x) B2O3 (0 ≤ x ≤ 0.48) glass network and the mutual transformation mechanism between each structural unit is helpful to explore the effects on macroscopic properties as the structural units change.