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Science 25 November 1994:
Vol. 266. no. 5189, pp. 1355 - 1357
DOI: 10.1126/science.266.5189.1355
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Articles

The Central Role of Broken Bond-Bending Constraints in Promoting Glass Formation in the Oxides

M. Zhang 1 and P. Boolchand 1

1 Department of Electrical and Computer Engineering, University of Cincinnati, Cincinnati, OH 45221, USA

A glass network of N atoms with n1 of the atoms with a coordination number of 1, and m2 of the atoms with a coordination number of 2 about which the bond-angle constraint is broken, will in general display a stiffness threshold (rigidity percolation threshold) when the average coordination increases to a critical value (r)c = 2.4 – 0.4 (n1 – m2)/N. Silica and sodium tellurate glasses provide model examples for which this general relation predicts the observed rigidity percolation threshold; this relation predicts the percolation threshold only if one includes broken bond-bending constraints due to bridging oxygen in the former network and nonbridging oxygen in the latter network. The rigidity percolation threshold in (Na2O)x,(TeO2)1–x glasses observed to occur near x sime 0.18 in tellurium-125 Lamb-Mössbauer factor measurments.

Submitted on June 14, 1994
Accepted on September 22, 1994


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Amorphous materials: Properties, structure, and durability: Constrained interactions, rigidity, adaptative networks, and their role for the description of silicates.
M. Micoulaut (2008)
American Mineralogist 93, 1732-1748
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