Abstract
The enthalpy changes ?H8 between a poly(vinyl acetate) glass formed by rapid cooling and the corresponding fully relaxed glass have been estimated at four temperatures below the glass transition. The values obtained were different to those expected by extrapolating liquid behavior below the glass transition and were found to agree well with the predictions of a simple expression for the combined main chain conformational and free volume contributions to enthalpy. Conformational contributions from the side chain alone were also considered but were not required to obtain agreement with experiment. It can be concluded that the side chains remained mobile below the glass transition and do not contribute to the heat capacity discontinuity at Tg. © 1997 John Wiley & Sons, Inc.
| Original language | English |
|---|---|
| Pages (from-to) | 1107-1116 |
| Number of pages | 10 |
| Journal | Journal of Polymer Science Part B: Polymer Physics |
| Volume | 35 |
| Issue number | 7 |
| Publication status | Published - May 1997 |
Keywords
- Conformational energy
- Enthalpy relaxation
- Free volume
- Glass transition
- Physical ageing
- Side chains