Abstract: Fragility is a concept that is often correlated with glass formability. It is generally defined in terms of dynamical aspects of the liquid, usually based on the rate of increase of the viscosity as a function of the inverse temperature scaled to the glass transition temperature, Tg (i.e. Tg/T). Our experimental studies of the temperature dependence of the liquid structure factor, S(q...

The entropically based nonlinear Adam-Gibbs equation is discussed in the context of phenomenologies for nonlinear enthalpy relaxation within the glass transition temperature range. In many materials for which adequate data are available, the nonlinear Adam-Gibbs parameters are physically reasonable and agree with those obtained from linear relaxation data and thermodynamic extrapolations. Obser...

We followed the first stages of liquid–liquid phase separation in an alkali-borosilicate glass by complex impedance spectroscopy at constant temperatures below and above the glass transition temperature, Tg. We found a new feature of the electrical conductivity behavior: at temperatures below Tg, the electrical conductivity, r, diminished with time, while above Tg, the electrical conductivity i...

The purpose of this paper is to study the molecular mobility of paracetamol molecules in their amorphous state below the glass transition temperature (Tg) in order to evaluate the thermodynamic driving force which allows the amorphous form to recrystallize under different polymorphic modifications. Samples were aged at temperatures of -15, 0, 6, and 12 degrees C for periods of time from 1 h to ...

This study investigated the effect of oxygen plasma treatment on the glass transition temperature of enzymatic hydrolysis lignin (EHL) derived from the production of bio-ethanol. Differential scanning calorimetry (DSC) was used to obtain the glass transition temperature (Tg) of EHL. The results showed that the Tg value of EHL under different heating rates ranged from 160 to 200 °C, and there wa...

A protocol was developed to measure the glass transition temperature (Tg) of brown rice kernels using dynamic mechanical thermal analysis (DMTA). In order to accommodate the sample requirements of the dynamic mechanical thermal analyzer and prevent moisture loss during experiments, kernels were first wrapped with a thin layer of parafilm and then a thin layer of aluminum foil. The wrapped kerne...

Research on rice drying and tempering has shown that high drying temperatures (up to 603C) and high moisture removal rates (up to 6 percentage points moisture content) can be used without reducing milling quality as long as sufficient tempering at a temperature above the glass transition temperature (Tg) is allowed between drying passes. Using drying air temperatures above the Tg of the rice si...

Specific heat spectroscopy was used to study the dynamic glass transition of ultrathin poly(2-vinyl pyridine) films (thicknesses: 405-10 nm). The amplitude and the phase angle of the differential voltage were obtained as a measure of the complex heat capacity. In a traditional data analysis, the dynamic glass transition temperature Tg is estimated from the phase angle. These data showed no thic...

We report that the common polyalcohol D-mannitol may have two amorphous phases related by a first-order transition. Slightly above its glass transition temperature Tg (284 K), the supercooled liquid (SCL) of D-mannitol transforms to a low-energy, apparently amorphous phase with stronger hydrogen bonds. The enthalpy of this so-called Phase X is approximately halfway between those of the known am...

Effects of ingredients on frozen state properties of wheat doughs were investigated using different thermal analysis techniques. Also, the water sorption properties and glass transition temperatures for different cereal materials were determined. DSC thermograms were obtained for different dough samples annealed at a few degrees below the onset temperature of ice melting of the material, then c...