Temperature and pressure dependence of relaxation near the glass transition

5 Temperature and pressure dependence of relaxation near the glass transition 

The shear-relaxation modulus can be expressed in terms of a distribution of relaxation times p(x), as in Equahon 7.37. While there is no fundamental 

It has been proposed that the shift factor is a function of fractional free volume, / = Vf / v  

This is similar to the Doolittle expression for viscosity. It is further assumed that near the glass transition  

If Equation 8.11 is used in Equation 8.10, the form of Equation 8.9 is obtained with  

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