Fast dynamics of H{sub 2}O in hydrous aluminosilicate glasses studied with quasielastic neutron scattering

Journal Article · Tue Feb 01 00:00:00 EST 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.71.064205· OSTI ID:20665123

Indris, Sylvio; Heitjans, Paul; Behrens, Harald; Zorn, Reiner; Frick, Bernhard ^[1]

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1. Institut fuer Physikalische Chemie und Elektrochemie, Universitaet Hannover, Callinstrasse 3-3A, D-30167 Hannover (Germany)

We studied the dynamics of dissolved water in aluminosilicate glasses with the compositions NaAlSi{sub 3}O{sub 8}{center_dot}0.3H{sub 2}O, NaAlSi{sub 3}O{sub 8}{center_dot}1.3H{sub 2}O and Ca{sub 0.5}AlSi{sub 3}O{sub 8}{center_dot}1.3H{sub 2}O using quasielastic neutron scattering. As shown by near-infrared spectroscopy on these samples, H{sub 2}O molecules are the predominant hydrous species in the water-rich glasses whereas OH groups bound to tetrahedrally coordinated cations are predominant at low water contents. Backscattering and time-of-flight methods were combined to investigate motional correlation times in the range between 0.2 ps and 2 ns. For the water-rich glasses an elastic scan between 2 K and 420 K shows that the dynamical processes set in at lower temperatures in the Ca-bearing glass than in the Na-bearing glass. This is corroborated by the broadening of the inelastic spectra S(Q,{omega}). The shape of the scattering function S(Q,t) suggests a distribution of activation barriers for the motion of hydrous species in the disordered structure of the glass. The distribution is narrower and the average activation energy is smaller in the Ca-bearing glass than in the Na-bearing glass. No indication for dynamics of hydrous species was found at temperatures up to 520 K in the water-poor glass NaAlSi{sub 3}O{sub 8}{center_dot}0.3H{sub 2}O containing dissolved water mainly in the form of OH groups. It is concluded that H{sub 2}O molecules are the dynamic species in the above-mentioned time regime in the water-rich glasses. The dynamic process is probably a rotation of H{sub 2}O molecules around their bisector axis.

• OSTI ID: 20665123
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 71, Issue 6; Other Information: DOI: 10.1103/PhysRevB.71.064205; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
ACTIVATION ENERGY
ALUMINIUM SILICATES
BACKSCATTERING
CALCIUM COMPOUNDS
GLASS
INFRARED SPECTRA
NEUTRON DIFFRACTION
QUASI-ELASTIC SCATTERING
SODIUM COMPOUNDS
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0400-1000 K
TIME-OF-FLIGHT METHOD
WATER