Glass strain point

Strain point Highest temperature from which the glass can be rapidly cooled without serious internal stress 1014 5 820 470... 

Figure 15.8 shows the temperature dependence of several glass compositions. Several temperatures are identified by viscosity the working temperature of a glass by 103 Pa s, the softening point by 4 x 106 Pa s, the anneal point by 2.5 x 1012 Pa s, and the strain point by 4 x 1013 Pa s. Glass objects are usually shaped... 

ASTM C598-88, Standard Test Method for Annealing Point and Strain Point of Glass by Beam Bending , Annual Book of ASTM Standards, American Society for Testing and Materials, Philadelphia, PA. 

In view of the multitude of observed deformation mechanisms it is useful at this point to examine the effects of external variables, especially that of ambient temperature, on the deformation behavior of semi-crystalline thermoplastics. At room temperature many of these polymers are above their glass transition point and owe their strength and stiffness to the crystalline phases. The first displacements start in the relatively soft amorphous layers, but the stress-strain curve is largely determined by the presence and arrangement of the crystals. Interlamellar slip has been identified as an important mechanism, but, in addition, crystalline deformation mechanisms occur at moderate strains The corresponding stress-strain curve shows an... 

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