Relation of bond connectivity to physical properties in IR-transmitting covalent chalcogenide glasses
- Arizona State Univ., Tempe, AZ (United States)
The chalcogenide glass-forming system provide attractive model systems for elucidating the phenomenology of viscous liquids and the glass transition. In these systems the authors can vary continuously the density of covalent bonds per bonded atom while varying the type of connections between atoms (e.g., one-fold with iodine, two-fold with selenium, three-fold with arsenic and four-fold, with germanium). The effect of these bonding topologies and connectivities on the viscous properties of the liquids, and on the changes in properties which occur at glass transition will be discussed. This paper will examine the extent to which various properties can be correlated simply using the average coordination number concept of the Phillips-Thorpe constraint (rigidity percolation) treatments, and give reasons why this is always sufficient to predict the behavior of a given system. The authors will then further examine where distinctions can be made between entropy and free volume theories for the properties of glass-forming liquids. Correlations between liquid fragility and the deviations from exponentiality in the relaxation functions and the importance of now-linearity in the relaxational response will be demonstrated, and compared with the broader correlations recently demonstrated for liquids of all types near the glass transition. Finally the connection between changes in the liquid properties will bond density and the solid state properties of the glass, e.g. density, rigidity, Poisson`s retro and photoconductivity, will be reviewed.
- OSTI ID:
- 141444
- Report Number(s):
- CONF-930304-; TRN: 93:003688-1121
- Resource Relation:
- Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
- Country of Publication:
- United States
- Language:
- English
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