Structural control on bulk melt properties: Single and double quantum Si-29 NMR spectroscopy on alkali-silicate glasses

Research areas:

• Intérieurs planétaires (2011 - 2016)

Year:

2007

Authors:

• Wim J. Malfait
• Werner E. Halter
• Yann Morizet
• Beat H. Meier
• Rene Verel

Journal:

GEOCHIMICA ET COSMOCHIMICA ACTA

Volume:

71

Number:

24

Pages:

6002-6018

Month:

DEC 15

ISSN:

0016-7037

BibTex:

@article{WOS:000251708000011, author = "Wim J. Malfait and Werner E. Halter and Yann Morizet and Beat H. Meier and Rene Verel", abstract = "The structure of 21 binary potassium, rubidium and cesium silicate glasses (in the range 15-50 mol% alkali oxide) was analyzed by Si-29 single quantum and double quantum MAS NMR spectroscopy. Their glass transition temperatures (T-g) were measured by calorimetry. The chemical shifts and the relative abundance of Q(n) species correlate with the cationic field strength (Z/r) of the network modifier. A correlation is observed between Tg and the inverse of the entropy of mixing of the different Q(n) species, which is explained in the framework of the Adam-Gibbs relaxation theory. At high alkali content, up to 44% of the SiO4 tetrahedra are part of three-membered rings. At a given alkali content, the abundance of these rings increases with increasing cation size. The abundance of three-membered rings in K-silicate melts correlates with a temperature and a non-linear composition dependence of the heat capacity. It is also a possible cause for the anomalous volumetric behavior of potassium silicate glasses. (C) 2007 Elsevier Ltd. All rights reserved.", doi = "10.1016/j.gca.2007.09.011", extra = "PICL", issn = "0016-7037", journal = "GEOCHIMICA ET COSMOCHIMICA ACTA", month = "DEC 15", number = "24", pages = "6002-6018", title = "{S}tructural control on bulk melt properties: {S}ingle and double quantum {S}i-29 {NMR} spectroscopy on alkali-silicate glasses", volume = "71", year = "2007", }

Abstract:

The structure of 21 binary potassium, rubidium and cesium silicate glasses (in the range 15-50 mol% alkali oxide) was analyzed by Si-29 single quantum and double quantum MAS NMR spectroscopy. Their glass transition temperatures (T-g) were measured by calorimetry. The chemical shifts and the relative abundance of Q(n) species correlate with the cationic field strength (Z/r) of the network modifier. A correlation is observed between Tg and the inverse of the entropy of mixing of the different Q(n) species, which is explained in the framework of the Adam-Gibbs relaxation theory. At high alkali content, up to 44% of the SiO4 tetrahedra are part of three-membered rings. At a given alkali content, the abundance of these rings increases with increasing cation size. The abundance of three-membered rings in K-silicate melts correlates with a temperature and a non-linear composition dependence of the heat capacity. It is also a possible cause for the anomalous volumetric behavior of potassium silicate glasses. (C) 2007 Elsevier Ltd. All rights reserved.