Topological Constraint Theory for Network Glasses and Glass-Forming Liquids: A Rigid Polytope Approach

Bibliographic Details
Title: Topological Constraint Theory for Network Glasses and Glass-Forming Liquids: A Rigid Polytope Approach
Authors: Sabyasachi Sen, Jeremy K. Mason
Source: Frontiers in Materials, Vol 6 (2019)
Publisher Information: Frontiers Media S.A., 2019.
Publication Year: 2019
Collection: LCC:Technology
Subject Terms: supercooled and glassy state, rigid polytope, activation entropy, glass transition, fragility, topological constraint theory, Technology
More Details: A variation of the topological constraint theory is proposed where an atomic network is modeled as a collection of rigid polytopes, and which explicitly distinguishes the bond angle constraints as well as rigid bond angles from flexible ones. The proposed theory allows for direct quantitative estimation of the fraction f of zero-frequency or floppy modes of the network. A preliminary model is proposed to connect the theory to the two key experimental observables that characterize glass-forming liquids, i.e., the glass transition temperature Tg and fragility m. The predicted values are tested against the literature data available for binary and ternary chalcogenides in the Ge-As-Se system. The Tg is related to f in this model by the activation entropy associated with the bond scission-renewal dynamics that is at the heart of transport and relaxation in glass-forming liquids. On the other hand, the large and temperature-dependent conformational entropy contribution of the 1-polytopes, i.e., the selenium chain elements in these chalcogenide glass-forming liquids, plays a key role in controlling the variation of m with f.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2296-8016
Relation: https://www.frontiersin.org/article/10.3389/fmats.2019.00213/full; https://doaj.org/toc/2296-8016
DOI: 10.3389/fmats.2019.00213
Access URL: https://doaj.org/article/fe4f4d08922c4029a6846b66e47e0449
Accession Number: edsdoj.fe4f4d08922c4029a6846b66e47e0449
Database: Directory of Open Access Journals
More Details
ISSN:22968016
DOI:10.3389/fmats.2019.00213
Published in:Frontiers in Materials
Language:English