Effect of Network Polymerization on the Pressure-Induced Structural Changes in Sodium Aluminosilicate Glasses and Melts: 27Al and 17O Solid-State NMR Study

Abstract

Probing the pressure-induced structural changes and the extent of disorder in aluminosilicate glasses and melts at high pressure remains a challenge in modern physical and chemical sciences. With an aim of establishing a systematic relationship between pressure, composition, and glass structures, we report 27Al and 17O 3QMAS NMR spectra for sodium aluminosilicate glasses [Na2O:Al2O3:SiO2 = 1.5:0.5:2n with n = 1 (NAS150520, XSiO2 = 0.5), 2 (NAS150540, XSiO2 = 0.67), and 3 (NAS150560, XSiO2 = 0.75)], quenched from melts at pressures up to 8 GPa. We also explore the stability of the [4]Al–O–[4]Al cluster in the highly depolymerized, NAS150520, glass at high pressure. For given glass composition, the [5,6]Al peak intensity increases with increasing pressure. The population of [5,6]Al increases linearly with XSiO2 from NAS150520 (XSiO2 = 0.5) to NAS150560 glass (XSiO2 = 0.75) at both 6 and 8 GPa. The [5,6]Al/XSiO2 ratio also tends to increase with pressure, indicating a possible relationship between [5,6]Al fr...