The fictive temperature (Tf) was defined by Tool in the 1940s as a measure of glassy structure. Tf is generally measured on heating and can be calculated from the enthalpy overshoot in calorimetric studies using a method developed by Moynihan. Prior work has demonstrated that the limiting fictive temperature (Tf′) is similar to Tg (measured on cooling) and depends on the cooling rate in a manner consistent with the Williams–Landel–Ferry (WLF) relationship. Theoretically, the limiting fictive temperature should not depend on heating rate, but this has been experimentally verified only for a very limited range of heating rates. Here, rapid-scanning chip calorimetry and conventional differential scanning calorimetry (DSC) are combined to investigate Tf′ for polystyrene over a broad range of heating rates ranging from 0.017 to 3000 K/s after cooling at different rates. The results show that Tf′ depends on cooling rate following the WLF equation. On the other hand, Tf′ is not a function of
|Pages (from-to)||Published Online August 2014; DOI:10.1016/j.tca.2014.08.019|
|State||Published - Aug 2014|
Simon, S., & Gao, S. (2014). Measurement of the limiting fictive temperature over five decades of cooling and heating rates. Thermochimica Acta, Published Online August 2014; DOI:10.1016/j.tca.2014.08.019.