Glass transition anomalies

In a supercooled liquid near the glass transition temperature, the self-consistent calculation is the only way to explain the anomalies in different dynamical quantities. As mentioned before, the first such self-consistent calculation was done by Geszti to explain the behavior of the viscosity near the glass transition temperature. He had argued that an increase in the viscosity slows down the structural relaxation and thus the relaxation of the density mode. This in turn increases the density mode contribution to the viscosity, t]spp... 

The orientational transition temperature goes down by about 12 K. The lattice parameter jump is less pronounced. The anomaly near the orientational glass transition (around 90 K) is smoothed out. 

Fig. 2. Maxima of the curves defining the equilibrium glass transition temperature. It is treated as a thermodynamic anomaly at which the most stable hole configuration is reached under the close packing of holes and flex bonds. R is the gas constant, z is the lattice coordinate number, and /ir(=/r) is the hole fraction at T, [11]...

Entered into (17), the square-root dependence of the plateau value translates into the square-root anomaly of the elastic constant Go, and causes the increase of the yield stress close to the glass transition. 

Annealing or other prehistory affects sub-Tg, Tg and post-Tg anomalies In specific heat and the expansion coefficients. Nonlinear relaxation effects In the glass transition kinetics depend on different parameters In models which can be used to describe the data. An extension of this theory must Include the data reported In this paper. The proposed clusters which can not be observed by X-rays are liq>ortant for alterations of the ultimate properties of glassy materials. 

The observed anomalies in the character of change in the glass transition temperatrrre of a soft phase of polyurethane block copolymers ditring plasticization and mechanical behavior of such materials can be explained if it is considered that the chemical stmcture of soft phase and hydrogen bonds distribution may significantly change. 

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