Demonstrated is an interactive fitting exercise for the Williams-Landel-Ferry (WLF) time-temperature equivalence relation, characteristic of certain viscoelastic materials. The first figure indicates physical test data, for example relaxation data, taken at a variety of temperatures. The curve indicated in red is the chosen reference temperature, frequently the glassy transition temperature.
The second figure indicates the same data after it was manually superimposed over the reference temperature, approximately forming a single curve. Note the expansion of the time scale with respect to the first figure.
The third figure represents the WLF fit of the temperature shifts taken from figure two.