the temperature is increased at a constant rate (n), while the test piece is initially strained and then held at
fixed elongation during the test. The resulting (nonisothermal relaxation) modulus Enoniso(T) varies during the temperature scan at the constant heating rate (n), and is seemingly a function of temperature.
By differentiating
Enoniso(T) with the respect to the temperature T, the
relaxation spectrum H0¼H(T) is obtained according to Eq. 2
[27–29]: