Free volume anomalies in mixed-cation glasses revealed by positron annihilation lifetime spectroscopy (PALS)

Malcolm D. Ingram, Steven J. Pas, Cornelia Cramer, Yong Gao, Anita J. Hill

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15 Citations (Scopus)


PALS experiments reveal a minimum in ortho-positronium (o-Ps) lifetimes and a maximum in the corresponding intensities that emerge when mixed-cation (Li/Na) borate glasses are heated from ambient temperatures up to 473 K. These free volume 'anomalies' appear to be a true manifestation of the mixed alkali effect (MAE). They are consistent with a mechanism of ion transport involving cooperation between hops of unlike cations, resulting in increased disturbance of the glass network. The result lends support to the dynamic structure model.

Original languageEnglish
Pages (from-to)1620-1623
Number of pages4
JournalPhysical Chemistry Chemical Physics
Issue number8
Early online date15 Mar 2005
Publication statusPublished - Mar 2005

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