Structural evidence of mixed alkali effect for aluminoborosilicate glasses

Abstract

The structure of mixed alkali aluminoborosilicate is quite difficult to explain due to the mixed alkali effect and interaction between multiple network formers, intermediate oxides, and network modifiers. To understand the complex behavior of these components in mixed alkali glasses, solid-state MAS NMR and Raman spectroscopy were performed. Various Raman peaks were specifically revealed, and all of which were highly associated with the degree of polymerization (DP) obtained by deconvolution of 800–1200 cm−1. A systematic change of the glass network was well explained to be a consequence of a strong relationship between DP and MAS NMR results of network formers (27Al and 11B). When alkali cations were mixed, a new characteristic of mixed alkali effect, an increase in charge compensation stability between AlO4 and smaller cation, was first observed from high correlation between full width at half maximum (FWHM) of network modifiers (7Li and 23Na) and MAS NMR data of network formers.