Details
| Original language | English |
|---|---|
| Article number | 064205 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 71 |
| Issue number | 6 |
| Publication status | Published - Feb 2005 |
Abstract
We studied the dynamics of dissolved water in aluminosilicate glasses with the compositions NaAlSi 3O 8·0.3H 2O, NaAlSi 3O 8·1.3H 2O and Ca 0.5AlSi 3O 8·1.3H 2O using quasielastic neutron scattering. As shown by near-infrared spectroscopy on these samples, H 2O 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 5(Q,ω). 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 3O 8·0.3H 2O containing dissolved water mainly in the form of OH groups. It is concluded that H 2O 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 2O molecules around their bisector axis.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Physical Review B - Condensed Matter and Materials Physics, Vol. 71, No. 6, 064205, 02.2005.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Fast dynamics of H 2O in hydrous aluminosilicate glasses studied with quasielastic neutron scattering
AU - Indris, Sylvio
AU - Heitjans, Paul
AU - Behrens, Harald
AU - Zorn, Reiner
AU - Frick, Bernhard
PY - 2005/2
Y1 - 2005/2
N2 - We studied the dynamics of dissolved water in aluminosilicate glasses with the compositions NaAlSi 3O 8·0.3H 2O, NaAlSi 3O 8·1.3H 2O and Ca 0.5AlSi 3O 8·1.3H 2O using quasielastic neutron scattering. As shown by near-infrared spectroscopy on these samples, H 2O 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 5(Q,ω). 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 3O 8·0.3H 2O containing dissolved water mainly in the form of OH groups. It is concluded that H 2O 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 2O molecules around their bisector axis.
AB - We studied the dynamics of dissolved water in aluminosilicate glasses with the compositions NaAlSi 3O 8·0.3H 2O, NaAlSi 3O 8·1.3H 2O and Ca 0.5AlSi 3O 8·1.3H 2O using quasielastic neutron scattering. As shown by near-infrared spectroscopy on these samples, H 2O 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 5(Q,ω). 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 3O 8·0.3H 2O containing dissolved water mainly in the form of OH groups. It is concluded that H 2O 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 2O molecules around their bisector axis.
UR - http://www.scopus.com/inward/record.url?scp=16244379871&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.71.064205
DO - 10.1103/PhysRevB.71.064205
M3 - Article
AN - SCOPUS:16244379871
VL - 71
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 1098-0121
IS - 6
M1 - 064205
ER -