Structural Change in the Process of
Permanent Densification of Fluorozirconate Glass
studied with Molecular Dynamics Simulations.
Y. Tamai, Y. Kawamoto
Phys. Rev., B 62, 865-873 (2000)
Abstract
Molecular dynamics simulations have been performed
on a fluorozirconate glass
(55ZrF4 17BaF2 5EuF3 23NaF)
in order to elucidate a mechanism of
the peculiar permanent densification behavior,
which was recently found by high-pressure experiments.
Structural changes in the glass
during the permanent densification process have been investigated in detail.
Under high pressures, changes in the connectivity
of network-forming ZrFn and EuFn polyhedra cause
the contraction of interstices around network-modifying
Ba2+ and Na+ ions,
accompanying an increase in the coordination numbers.
The glass network structures under high pressures
are fully or partially preserved even after decompression
at far or moderately lower temperatures than Tg.
The partial preservation of the connectivity of network-forming polyhedra
causes maxima in treatment-pressure dependencies of structural relaxation
in the F- coordination environments around the network-modifying ions.
This is responsible for the peculiar permanent densification behavior.
Copyright (c) 2000 Yoshinori Tamai