Effect of composition on structural evolution and NMR parameters of quadrupolar nuclides in sodium borate and aluminoborosilicate glasses: a view from high-resolution 11B, 27Al, and 17O solid-state NMR

In this study, using B-11, Al-27, and O-17 3QMAS NMR spectroscopy, we investigated the compositional effect on the structures (particularly, topological evolution of boron species and their spatial proximity) and the NMR parameters of B, Al, and O configurations in binary sodium borate and sodium aluminobomsilicate glasses in NaBSiO4-NaAlSiO4 and NaBSi3O8-NaAlSi3O8 joins. Noble structural findings of the current study include the two distinct B-[4] species in sodium borate glasses with low alkali content and the presence of Na-O-B peak in NaAl0.25B0.75SiO4 glasses. The proximity between B-[3] and B-[4] in NaAlSiO4-NaBSiO4 glasses was revealed via B-11 double quantum MAS NMR. The changes in quadrupolar coupling constants and isotropic chemical shift for diverse coordination B and Al environments and oxygen clusters provide improved insights in the effect of composition on the changes in the 2nd nearest neighbors environments and the extent of topological distortion.