Response of complex networks to compression: Ca, La, and Y aluminoborosilicate glasses formed from liquids at 1 to 3 GPa pressures
- Department of Geological Sciences, Stanford University, Stanford, California 94305 (United States)
- Department of Chemistry, Stanford University, Stanford, California 94305 (United States)
Aluminoborosilicate glasses containing relatively high field strength modifiers (Ca, La, and Y) have been compressed at pressures up to 3 GPa and near the glass transition temperature (T{sub g}) and quenched to room temperature at high pressure followed by decompression. Structural changes were quantified with high-resolution {sup 27}Al and {sup 11}B MAS nuclear magnetic resonance at 14.1–18.8 T. The changes with pressure in Al and B coordinations in the recovered samples are quite large with more than 50% decreases in tetrahedral aluminum ({sup IV}Al) and 200%-300% increases in tetrahedral boron ({sup IV}B). Glasses with higher field strength modifiers (La and Y) contain more high coordinated aluminum ({sup V,V} {sup I}Al) at all pressures studied. More high coordinated boron also correlates with higher field strength modifier if all three compositions are compared on an isothermal basis. Although lowering fictive temperature and increasing pressure both increase Al and B coordinations, our study shows that the actual mechanisms for structural changes are most probably different for temperature and pressure effects. Using a rough thermodynamic model to extrapolate to higher pressures, it appears that a simple non-bridging oxygen (NBO) consumption mechanism is not sufficient to convert all the aluminum to octahedral and boron to tetrahedral coordination, suggesting other mechanisms for structural changes could occur at high pressure as NBO becomes depleted.
- OSTI ID:
- 22493696
- Journal Information:
- Journal of Chemical Physics, Vol. 144, Issue 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM
ALUMINIUM 27
ALUMINIUM COMPOUNDS
BORON
BORON 11
BOROSILICATE GLASS
CALCIUM COMPOUNDS
COMPARATIVE EVALUATIONS
LANTHANUM COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
PRESSURE DEPENDENCE
PRESSURE RANGE GIGA PA
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS