Specific Heat and Transport “Anomalies” in Mixed Alkali Glasses

Author

Peter F. Green
Richard K. Brow, Missouri University of Science and TechnologyFollow
James J. Hudgens

Abstract

We show that changes in the relative mole fractions of Li₂O and Na₂O in alkali metaphosphate glasses lead to “anomalies” in the specific heat and structural relaxations. The heat capacity change between the liquid and glassy states, Δc_p(T_g), at the calorimetric glass transition temperature, T_g, exhibits a minimum when the mole fractions of Li₂O and Na₂O are comparable. Moreover, systematic changes in the temperature dependence of the viscosity, η, i.e., changes in the “fragility” of the system, accompany these changes in mole fraction. This observed dependence of the “fragility” on the mixed alkali ion composition occurs in the absence of apparent changes in the covalent network connectivity which normally accounts for this behavior in glasses.

Recommended Citation

P. F. Green et al., "Specific Heat and Transport “Anomalies” in Mixed Alkali Glasses," Journal of Chemical Physics, vol. 109, no. 18, pp. 7907 - 7912, American Institute of Physics (AIP), Nov 1998.

The definitive version is available at https://doi.org/10.1063/1.477438

Department(s)

Materials Science and Engineering

International Standard Serial Number (ISSN)

0021-9606

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 1998 American Institute of Physics (AIP), All rights reserved.

Publication Date

08 Nov 1998