The Thermodynamics of the Glass Transition

1981 ◽  
Vol 8 ◽  
Author(s):  
Mats Hillert
Keyword(s):  
Glass Transition ◽  
Kinetic Theory ◽  
Thermodynamic Description ◽  
Amorphous State ◽  
Gradual Process

ABSTRACTThe kinetic theory of the glass transition is examined. Some modifications are suggested in order to overcome some shortcomings. As a result, a thermodynamic description of the glass transition is obtained. It is demonstrated that the glass transition represents the beginning of a very gradual process of melting in the amorphous state.

Differential Scanning Calorimetry (DSC) Analysis of Abaca Fibre (Musa Textile Nee) Reinforced High Impact Polystyrene (HIPS) Composites

2011 ◽  
Vol 295-297 ◽  
pp. 929-933 ◽  
Author(s):  
E.H. Agung ◽  
S.M. Sapuan ◽  
M.M.H. Megat Ahmad ◽  
H.M.D.K. Zaman ◽  
U. Mustofa
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Optimum Condition ◽  
Amorphous State ◽  
Heat Content ◽  
High Impact ◽  
Glass Transitions ◽  
Scanning Calorimetry ◽  
High Impact Polystyrene

Differential scanning calorimetry (DSC) was used to study the thermal behaviour of abaca fibre reinforced high impact polystyrene (HIPS) composites. Thermal analysis is based upon the detection of changes in the heat content (enthalpy) and the glass transition temperature (Tg) of optimum condition of abaca fibre reinforced HIPS composites. In this research, glass transitions temperature (Tg) of neat HIPS occurred below the Tg of optimum condition of composites as the temperature of an amorphous state. The endothermic peak of composites was in to range 430-435°C including neat HIPS and it observed that enthalpy of abaca fibre reinforced HIPS composites yielded below the neat HIPS 748.79 J/g.

Modern aspects of the kinetic theory of glass transition

2016 ◽  
Vol 186 (1) ◽  
pp. 47-73 ◽  
Author(s):  
Timur V. Tropin ◽  
Juern W.P. Schmelzer ◽  
Viktor L. Aksenov
Keyword(s):  
Glass Transition ◽  
Kinetic Theory

Luminescence différée d'une solution organique vitreuse photoactivée et transition vitreuse

1977 ◽  
Vol 55 (13) ◽  
pp. 2517-2522 ◽  
Author(s):  
D. Ceccaldi
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Kinetic Theory ◽  
Rise Time ◽  
Time Dependent ◽  
Glassy Matrix ◽  
Temperature Dependent

A general kinetic theory is used to explain the shapes of photoionized sample luminescence curves perturbed by thermal jumps (Δ ∼ 1 K, rise time ∼ 1 s). The samples studied are photoactivated organic vitreous solutions of TMPD/MCH 10−3 M and TMPD/3-MP 10−3 M. The experiments are performed within a temperature range (63–91 K) which includes the glass transition temperature Tg. It is shown that there is a slow diffusion of the trapped electrons towards the cation and competition between thermal detrapping and tunneling. The tunneling/thermal detrapping ratio Y is not time dependent during an isothermal luminescence and is only slowly temperature dependent if T ≤ Ty. Ty is very close to Tg. For T > Ty, Y decreases rapidly with T. The activation energy for thermal detrapping shows a maximum when the temperature reaches [Formula: see text] The glass transition temperature Tg may therefore be defined empirically as:[Formula: see text]Finally we obtain a glassy matrix relaxation time, τ, which decreases with T.

Miscibility, Isothermal Crystallization/Melting Behavior and Morphology of Poly(Trimethylene Terephthalate)/Poly(Buthylene Terephthalate) Blends

2008 ◽  
Vol 54 ◽  
pp. 243-248 ◽  
Author(s):  
Pongpipat Krutphun ◽  
Pitt Supaphol
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Amorphous State ◽  
Minor Component ◽  
The Body ◽  
Nucleation Theory ◽  
Melting Point Depression ◽  
Melt Crystallization ◽  
Trimethylene Terephthalate

Blends of poly(trimethylene terephthalate) (PTT) and poly(buthylene terephthalate) (PBT) in the amorphous state were miscible in all of the blend compositioins studied, as evidenced by a single, composition-dependent glass-transition temperature observed for each blend composition. The variation in the glass-transition temperature was well-predicted by the Gordon- Taylor equation, with the fitting parameter being 1.37. The cold-crystallization (peak) temperature increased with increasing PBT content in the blends. The subsequent melting endotherms after melt crystallization exhibited melting point depression behavior in which the observed melting temperatures decreased with an increasing amount of minor component of the blends. LHW and NLHW were used to determine the equilibrium melting temperature of the blends. The values of the overall crystallization rate parameters for these blends were all found to increase with decreasing crystallization temperature, suggesting that these blends crystallized at low temperatures faster than that at high temperatures. As the content of PBT was further increased, these values dramatically decreased. This result is similar to that observed in the growth rate. From LH secondary nucleation theory, PTT ,PBT and their blends showed the transition temperatures between regime III and II about 194oC. Banded spherulites were observed for PTT/PBT blends. The spacing of bands of PTT increases with increasing Tc. The body of spherulite texture is more open with increasing PBT content. In addition, the boundary of spherulite is also changed with composition.

Modern aspects of the kinetic theory of glass transition

2016 ◽  
Vol 59 (1) ◽  
pp. 42-66 ◽  
Author(s):  
T V Tropin ◽  
J W Schmelzer ◽  
V L Aksenov
Keyword(s):  
Glass Transition ◽  
Kinetic Theory
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