Abstract
In a recent paper, Hermansen, Mauro, and Yue [J. Chem. Phys. 140, 154501 (2014)] applied the temperature-dependent constraint theory to model both the glass transition temperature, Tg, and fragility, m, of a series of binary alkali phosphate glasses of the form R 2 O x P 2 O 5 1 - x, where R represents an alkali species. Key to their success seems to be the retention of linear constraints between the alkali ion (R+) and the non-bridging oxygens near Tg, which allows the model to mimic a supposed minimum for both Tg(x) and m(x) located near x = 0.2. However, the authors have overlooked several recent studies that clearly show there is no minimum in m(x). We argue that the retention of the alkali ion constraints at these temperatures is unjustified and question whether the model calculations can be revised to meet the actual experimental data. We also discuss alternative interpretations for the fragility based on two-state thermodynamics that can accurately account for its compositional dependence.
| Original language | English |
|---|---|
| Article number | 107103 |
| Journal | Journal of Chemical Physics |
| Volume | 142 |
| Issue number | 10 |
| DOIs |
|
| State | Published - Mar 14 2015 |
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
Cite this
A model for phosphate glass topology considering the modifying ion sub-network (Journal of Chemical Physics (2014) 140 (154501)). / Sidebottom, David L.
In: Journal of Chemical Physics, Vol. 142, No. 10, 107103, 14.03.2015.Research output: Contribution to journal › Comment/debate
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TY - JOUR
T1 - A model for phosphate glass topology considering the modifying ion sub-network (Journal of Chemical Physics (2014) 140 (154501))
AU - Sidebottom, David L.
PY - 2015/3/14
Y1 - 2015/3/14
N2 - In a recent paper, Hermansen, Mauro, and Yue [J. Chem. Phys. 140, 154501 (2014)] applied the temperature-dependent constraint theory to model both the glass transition temperature, Tg, and fragility, m, of a series of binary alkali phosphate glasses of the form R 2 O x P 2 O 5 1 - x, where R represents an alkali species. Key to their success seems to be the retention of linear constraints between the alkali ion (R+) and the non-bridging oxygens near Tg, which allows the model to mimic a supposed minimum for both Tg(x) and m(x) located near x = 0.2. However, the authors have overlooked several recent studies that clearly show there is no minimum in m(x). We argue that the retention of the alkali ion constraints at these temperatures is unjustified and question whether the model calculations can be revised to meet the actual experimental data. We also discuss alternative interpretations for the fragility based on two-state thermodynamics that can accurately account for its compositional dependence.
AB - In a recent paper, Hermansen, Mauro, and Yue [J. Chem. Phys. 140, 154501 (2014)] applied the temperature-dependent constraint theory to model both the glass transition temperature, Tg, and fragility, m, of a series of binary alkali phosphate glasses of the form R 2 O x P 2 O 5 1 - x, where R represents an alkali species. Key to their success seems to be the retention of linear constraints between the alkali ion (R+) and the non-bridging oxygens near Tg, which allows the model to mimic a supposed minimum for both Tg(x) and m(x) located near x = 0.2. However, the authors have overlooked several recent studies that clearly show there is no minimum in m(x). We argue that the retention of the alkali ion constraints at these temperatures is unjustified and question whether the model calculations can be revised to meet the actual experimental data. We also discuss alternative interpretations for the fragility based on two-state thermodynamics that can accurately account for its compositional dependence.
UR - http://www.scopus.com/inward/record.url?scp=84924873673&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84924873673&partnerID=8YFLogxK
U2 - 10.1063/1.4913760
DO - 10.1063/1.4913760
M3 - Comment/debate
AN - SCOPUS:84924873673
VL - 142
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 10
M1 - 107103
ER -