A comparative study on the structural aspects of sodium borosilicate glasses and barium borosilicate glasses: Effect of Al2O3 addition

摘要

Sodium borosilicate and barium borosilicate glasses containing different amounts of Al2O3 were prepared by conventional melt-quench method and their structural information was obtained by Si-29, B-11 and Al-27 Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) technique. By employing the Dell and Bray model, different types of boron and silicon structural units present in the glass have been identified. The relative concentrations of BO3 and BaT structural units evaluated from the B-11 MAS NMR patterns match (within experimental errors) with that predicted by Dell and Bray model. Al3+ ion exists only as AlO4- structural units with Si-O-Al type of linkages in the glass. Higher glass transition temperature of barium borosilicate glass compared to sodium borosilicate glass has been attributed to the formation of relatively more connected BO structural units at the expense of less connected BO3 structural units in the former glass. (C) 2016 Elsevier B.V. All rights reserved.