Glassy state, crystallization from

Wang, C., Lin, C-C., Chu, C-P. Crystallization and morphological features of syndiotactic polystyrene induced from glassy state. Polymer, 46, 12595-12606 (2005). 

Growth from glassy state spin line 94 quenched and subsequently crystallized liber birefringence development using LDT on hot stage assembly between crossedpolars.Amorphous condition verified X-ray diffraction... 

Figure 3. DSC traces for PVDFiPVAc blends upon heating at 5 °C/min from glassy state at -60 °C. Traces are identified by their respective PVDF content in wt%. The presence of two endothermic peaks indicates that two PVDF crystal structures were formed during crystallization.

There are other conditions that result from the frozen-in stresses. In materials such as crystal polystyrene, which have low elongation to fracture and are in the glassy state at room temperature, a frequent result is crazing it is the appearance of many fine microcracks across the material in a direction perpendicular to the stress direction. This result may not appear immediately and may occur by exposure to either a mildly solvent liquid or vapor. Styrene products dipped in kerosene will craze quickly in stressed areas. 

Fig. 4 SAXS curves of PET crystallized from the glassy state at 80 °C as a function of annealing time [7]...

Jabarin, S. A., Crystallization kinetics of polyethylene terephthalate. III. Effect of moisture content on the crystallization behaviour of PET from the glassy state, J. Appl. Polym. Sci., 34, 103-108 (1987). 

Figure 7.2 Crystallization half-times for PET and PCT from (a) the glassy state, and (b) the melt...

The data for the isothermal crystallization of [IX-Cg] from the glassy state were analyzed by the same method as that for the polyethers. Avrami s index obtained was between 2.1 and 2.2, i.e., n = ca. 2. This value, n = 2, suggests that the crystals grow two-dimensionally, if the nucleation process is heterogeneous and the growth process is diffusion-controlled. 

Below T0 the material is in the glassy state. Compared with the crystal the glass shows a larger specific volume and heat content, but both quantities have a smaller temperature coefficient than in the melt (< ). The transition from melt to glass is often called a transition of the second order (2, 3) since it is not accompanied by finite changes of volume and enthalpy, but only by changes of their temperature coefficients. 

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