Polymers—Five Regions of Viscoelasticity

FIGURE 9.5 Typical analysis of torsion pendulum, (a) Oscillating trace made by the tip of moment arm gives a period of 1.67 s corresponding to a frequency of 0.600 Hz or 1.20 n rad/s. (b) Plot according to Equation 9.34 gives a logarithmic decrement of 0.23. 

The significance of this generalization cannot be overstated for materials such as polymers, which manifest time-dependent behavior. Again and again, we find in the literature the methods of superposing time and temperature for mechanical and other properties in amorphous and partially amorphous materials. Remarkably, whatever modifications are introduced usually reduce the behavior back in the direction of Equation 9.40. 

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