Free volume anomalies in mixed-cation glasses revealed by positron annihilation lifetime spectroscopy (PALS)
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 t...
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Published in | Physical chemistry chemical physics : PCCP Vol. 7; no. 8; p. 1620 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
21.04.2005
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Subjects | |
Online Access | Get more information |
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Summary: | 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. |
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ISSN: | 1463-9076 |
DOI: | 10.1039/b419201j |