Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy
New Raman and NMR spectroscopy data on hydrous Ca aluminosilicate melts and glasses, with eutectic quartz–anorthite–wollastonite composition, are presented here. The glasses were obtained by rapid quench of melts equilibrated at high P and high T in a piston–cylinder apparatus. In situ Raman observa...
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| Format: | Article |
| Language: | English |
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Académie des sciences
2022-05-01
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| Series: | Comptes Rendus. Géoscience |
| Subjects: | |
| Online Access: | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.127/ |
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| author | Le Losq, Charles Mysen, Bjorn O. Cody, George D. |
| author_facet | Le Losq, Charles Mysen, Bjorn O. Cody, George D. |
| author_sort | Le Losq, Charles |
| collection | DOAJ |
| description | New Raman and NMR spectroscopy data on hydrous Ca aluminosilicate melts and glasses, with eutectic quartz–anorthite–wollastonite composition, are presented here. The glasses were obtained by rapid quench of melts equilibrated at high P and high T in a piston–cylinder apparatus. In situ Raman observations of the structure of the melts were also performed during hydrothermal diamond cell experiments. Using the intensities of the ${\sim }860~\text{cm}^{-1}$ and ${\sim }1630~\text{cm}^{-1}$ Raman signals, respectively assigned to vibrations of T–OH and $\text{H}_2\text{O}_{\mathrm{mol}}$ species, we determined the speciation of water in the glasses. T–OH and $\text{H}_2\text{O}_{\mathrm{mol}}$ values compare well with those determined from infrared (IR) spectra, except above ${\sim }5$ wt% total water where IR determinations actually underestimate the proportion of hydroxyl groups. The analysis of the polarized Raman spectra and of the ${}^{29}\text{Si}$ MAS NMR spectra of the hydrous glasses suggests limited changes in glass polymerization with variations in dissolved water content. However, at high temperatures, in situ Raman spectroscopy observations indicate that the hydrous melt structure differs very strongly from that of a glass containing a comparable concentration of dissolved water. Because of this, this study reinforces the fact that using glass data to try understanding high temperature processes in hydrous melts, like viscous flow or water diffusion toward bubbles during volcanic degassing, may not be very appropriate. |
| first_indexed | 2024-03-10T07:23:10Z |
| format | Article |
| id | doaj.art-63301499c2a54ac18b688c6d491efe4d |
| institution | Directory Open Access Journal |
| issn | 1778-7025 |
| language | English |
| last_indexed | 2024-03-10T07:23:10Z |
| publishDate | 2022-05-01 |
| publisher | Académie des sciences |
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| series | Comptes Rendus. Géoscience |
| spelling | doaj.art-63301499c2a54ac18b688c6d491efe4d2023-11-22T14:29:14ZengAcadémie des sciencesComptes Rendus. Géoscience1778-70252022-05-01354S119922510.5802/crgeos.12710.5802/crgeos.127Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopyLe Losq, Charles0https://orcid.org/0000-0001-8941-9411Mysen, Bjorn O.1https://orcid.org/0000-0002-2770-4273Cody, George D.2https://orcid.org/0000-0003-4176-3648Earth Planets Laboratory, Carnegie Institution for Science, Washington D.C. 20015, USA; Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, FranceEarth Planets Laboratory, Carnegie Institution for Science, Washington D.C. 20015, USAEarth Planets Laboratory, Carnegie Institution for Science, Washington D.C. 20015, USANew Raman and NMR spectroscopy data on hydrous Ca aluminosilicate melts and glasses, with eutectic quartz–anorthite–wollastonite composition, are presented here. The glasses were obtained by rapid quench of melts equilibrated at high P and high T in a piston–cylinder apparatus. In situ Raman observations of the structure of the melts were also performed during hydrothermal diamond cell experiments. Using the intensities of the ${\sim }860~\text{cm}^{-1}$ and ${\sim }1630~\text{cm}^{-1}$ Raman signals, respectively assigned to vibrations of T–OH and $\text{H}_2\text{O}_{\mathrm{mol}}$ species, we determined the speciation of water in the glasses. T–OH and $\text{H}_2\text{O}_{\mathrm{mol}}$ values compare well with those determined from infrared (IR) spectra, except above ${\sim }5$ wt% total water where IR determinations actually underestimate the proportion of hydroxyl groups. The analysis of the polarized Raman spectra and of the ${}^{29}\text{Si}$ MAS NMR spectra of the hydrous glasses suggests limited changes in glass polymerization with variations in dissolved water content. However, at high temperatures, in situ Raman spectroscopy observations indicate that the hydrous melt structure differs very strongly from that of a glass containing a comparable concentration of dissolved water. Because of this, this study reinforces the fact that using glass data to try understanding high temperature processes in hydrous melts, like viscous flow or water diffusion toward bubbles during volcanic degassing, may not be very appropriate.https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.127/MeltGlassStructureWaterSpeciationRamanNMR |
| spellingShingle | Le Losq, Charles Mysen, Bjorn O. Cody, George D. Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy Comptes Rendus. Géoscience Melt Glass Structure Water Speciation Raman NMR |
| title | Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy |
| title_full | Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy |
| title_fullStr | Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy |
| title_full_unstemmed | Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy |
| title_short | Water solution mechanism in calcium aluminosilicate glasses and melts: insights from in and ex situ Raman and ${}^{29}\protect \text{Si}$ NMR spectroscopy |
| title_sort | water solution mechanism in calcium aluminosilicate glasses and melts insights from in and ex situ raman and 29 protect text si nmr spectroscopy |
| topic | Melt Glass Structure Water Speciation Raman NMR |
| url | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.127/ |
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