In order to fabrication of transparent glass-ceramics with Li-mica nano crystals, the glasses with chemical composition of 94.9 mass% Li(1+x)Mg3AlSi3(1+x)F2 (x=0.5) with 5.1 mass% MgF2 were crystallized. The glasses were fabricated via the conventional melt-quenching technique. Mica crystals were precipitated in the glass phase by later heat treatment. Glass samples had glass transition tempera...

Europium doped transparent lead fluorophosphate glass ceramics successfully were prepared with heat treatment of precourse glasses at temperature above glass transition (Tg). X-ray diffraction (XRD) experiment evidenced the formation of PbF2 nanocrystals in glassy matrix. The emission spectra investigation indicate that considerable amount of Eu3+ ions were trapped in crystalline phase, and the...

We perform molecular dynamics simulations of the glass transition through isobaric and isochoric cooling of a model polymeric material. In general, excellent agreement between the simulation results and the existing experimental trends is observed. The glass transition temperature (Tg) is found to be a function of pressure under isobaric conditions and specific volume under isochoric conditions...

in order to fabrication of transparent glass-ceramics with li-mica nano crystals, the glasses with chemical composition of 94.9 mass% li(1+x)mg3alsi3(1+x)f2 (x=0.5) with 5.1 mass% mgf2 were crystallized. the glasses were fabricated via the conventional melt-quenching technique. mica crystals were precipitated in the glass phase by later heat treatment. glass samples had glass transition tempera...

the glass transition temperature (tg) and the melting temperature (tm) of gelatin at water contents between 7 and 14% were measured using differential scanning calorimetry.  the plasticisation of the polymer by water led to a decrease in tg and tm. the tg of partially crystalline gelatin was higher than that of the amorphous one obtained by quenching from the melt. the enthalpy relaxation occur...

Comparisons are made of the translational and rotational diffusion of small-molecule probes in a polymer near its glass transition temperature, Tg . In the rubbery state, 1.1Tg . T . Tg, translational diffusion is much less temperature dependent than rotational reorientation; in a “quenched” glass, translation and rotation have similar temperature dependencies. This is explained to be a consequ...

The experimental technique offered by temperature-modulated differential scanning calorimeter (TMDSC) used to investigate the thermal relaxation dynamics through the glass transition as a function of frequency was studied for pure PMMA and PMMA-single wall carbon nanotubes (SWCNTs) composites. A strong dependence of the temperature dependence peak in the imaginary part of complex heat capacity ...

A fundamental problem of glass transition is to provide a quantitative and microscopic explanation of the heat-capacity jump at the glass transition temperature Tg . Similar problems are also common to other disordered systems, including spin glasses. We propose that the jump of heat capacity at Tg takes place as a result of the change of the liquid’s elastic, vibrational, and thermal propertie...

The problems posed by glass are not only practical but also conceptual: despite the progress afforded by advances in glass science, we still lack a complete understanding of how a liquid becomes a glass. Indeed, in contrast to most phase transitions, many measureable physical and chemical glass properties change smoothly across the liquid-to-glass transition at the glass transition temperature ...

Most low water content or frozen food products are partly or fully amorphous. This review will discuss the extent to which it is possible to understand and predict their behavior during processing and storage, on the basis of glass transition temperature values (Tg) and phenomena related to glass transition. Two main conclusions are provisionally proposed. Firstly, glass transition cannot be co...