Specific heat and transport {open_quotes}anomalies{close_quotes} in mixed alkali glasses
- Texas Materials Institute, Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062 (United States)
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
We show that changes in the relative mole fractions of Li{sub 2}O and Na{sub 2}O in alkali metaphosphate glasses lead to {open_quotes}anomalies{close_quotes} in the specific heat and structural relaxations. The heat capacity change between the liquid and glassy states, {Delta}c{sub p}(T{sub g}), at the calorimetric glass transition temperature, T{sub g}, exhibits a minimum when the mole fractions of Li{sub 2}O and Na{sub 2}O are comparable. Moreover, systematic changes in the temperature dependence of the viscosity, {eta}, i.e., changes in the {open_quotes}fragility{close_quotes} of the system, accompany these changes in mole fraction. This observed dependence of the {open_quotes}fragility{close_quotes} 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. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 663689
- Journal Information:
- Journal of Chemical Physics, Vol. 109, Issue 18; Other Information: PBD: Nov 1998
- Country of Publication:
- United States
- Language:
- English
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