Na+/K+ ion exchange in silicate glasses: Results from 17O 3QMAS NMR

• Published in: Journal of non-crystalline solids Vol. 475; pp. 190 - 194
• Main Authors: Ragoen, C., Marple, M.A.T., Sen, S., Boland, F., Godet, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2017
• Subjects: Alkali distribution; Glass; Ion exchange; Mixed-alkali effect; NMR; Alkali distribution; NMR; Ion exchange; Mixed-alkali effect; Glass
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2017.09.003

The effect of Na+/K+ ion exchange on the distribution of the modifier ions and on their interaction with the oxygen atoms in the network is investigated in ternary Na,Mg- and Na,Ca- silicate glasses using 17O triple-quantum magic-angle-spinning nuclear magnetic resonance spectroscopy. The results indicate that the K+ ions preferentially exchange with the Na+ ions present in {Na,Ca}-NBO and {Na,Mg}-NBO environments, while the Na-NBO environment is not significantly affected. Remelting of the ion-exchanged glasses leads to a homogenization of the modifier ion distribution around the NBO sites. The dynamical site preference for the Na+/K+ ion exchange has far-reaching implications in our understanding of the alkali ion transport and more specifically of the mixed-alkali effect in silicate glasses. •The distribution of modifier cations in silicate glass before and after the Na+/K+ ion exchange is investigated.•During ion exchange K+ displays a strong preference for Na+ in the mixed {Na,Ca}-NBO environments.•This dynamical site preference has important implications in understanding the mixed-alkali effect.