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Updated: Sep 22, 2025

Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films
Published on: January 26, 2016
Free Volume in the Melt and How It Correlates with Experimental Glass Transition Temperatures: Results for a Large
Ronald P White1, Jane E G Lipson1
1Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States.
Abstract:
There is a continuing, strong interest in making connections between the polymeric glass transition (Tg) and bulk properties. In this Letter we apply the Locally Correlated Lattice (LCL) model to study a group of 51 polymers and demonstrate two broad correlations. In the first, we show that the theoretically determined polymeric free volume in the melt, all at a single common T, P (425 K, 1 atm), correlates noticeably with the experimentally determined Tg values, and that this trend sharpens considerably when families of polymers are examined. Further, we show a strikingly linear correlation between the experimental Tg and the LCL model calculation for the percent free volume expected at the polymeric Tg. We suggest that this trend has a predictive value, acting as a boundary of T-dependent minimum-required free volume separating the melt and glassy regimes. Our theoretical estimates of free volume values at a polymer's Tg range between 4 and 16%, and their evident temperature dependence indicates an important role for temperature in glassification.
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