Quantification of boron in aluminoborosilicate glasses using Raman and 11B NMR

Abstract

Bulk methods and 11B Nuclear Magnetic Resonance were used to propose a calibration curve to determine the total B2O3 and the boron speciation using the non-destructive and the non-quantitative nature of Raman spectroscopy. The calibration was established from the analyses of 21 aluminoborosilicate glasses synthesised at 1 atm. and 1150 °C and an additional standard aluminoborosilicate glass. The studied glasses have composition in the Na2O-CaO-Al2O3-SiO2-B2O3 system with total B2O3 from 4.7 to 46.6 mol%.Raman spectra exhibit signatures in the 800–1200 and 1200–1600 cm−1 region corresponding to the symmetric stretches of silicate (HF) and borate networks (BO), respectively. The integrated area ratio (AB-O−/AHF) is correlated to the total mol.% B2O3. The mol.% B2O3 data are reproduced within 15% from the Raman spectra.Boron speciation from 11B NMR is correlated to the AB-O−/AHF determined by Raman; however, the mol.% BO4 appears also dependent on the Al2O3 content. We derived a multiple linear regression estimating the mol.% BO4 as a function of AB-O−/AHF and mol.% Al2O3. Results are valid for the investigated glasses and additional work is needed to better constrain the speciation model.