Tutorial TTSF Application

This short tutorial shows how to inspect time-temperature superposition shift factors and compare them with the built-in WLF or Arrhenius theories.

Load Shift-Factor Data

  1. Start RepTate and create a new TTS Factors application.

  2. Open a .ttsf file containing shift factors. The file should include the sample molar mass Mw as a file parameter and three data columns: temperature T in degrees Celsius, horizontal shift factor aT, and vertical shift factor bT.

Inspect Views

Use the View selector to switch between the shift-factor representations:

  • log(aT) plots \(\log_{10}(a_T)\) against temperature.

  • aT plots the horizontal shift factor against temperature with a logarithmic vertical axis.

  • log(bT) and bT show the corresponding vertical shift factor.

  • log(aT, bT) displays both logarithmic shift factors in the same plot.

  • log(aT) vs 1/T plots \(\log_{10}(a_T)\) against \(1/(T+273.15)\), which is useful when checking Arrhenius-like behavior.

The logarithmic views require positive aT or bT values.

Add a Shift-Factor Theory

  1. In the theory selector, choose WLF to compare the data with a Williams-Landel-Ferry shift law. The WLF calculation uses the file parameter Mw and theory parameters such as Tr, B1, B2, logalpha, and CTg.

  2. Click Calculate to evaluate the current theory parameters. Use Minimize Error only when you want RepTate to fit the adjustable WLF parameters to the loaded shift-factor data.

  3. For a single-file Arrhenius check, choose ArrheniusTheory instead. This theory calculates aT from the reference temperature Tref and activation energy Ea.