It is well known that there is an equivalence of the effects of time and temperature on the rheological properties of viscoelastic materials1. At low temperatures a material will behave in the same fashion as at high frequency, and at high temperature the material will behave as it would at low frequency. Data in a range of temperatures over modest frequency ranges( see figure 1) can be collected and arranged to predict the behavior over a wider frequency range than possible in practical testing. Bear in mind that very low frequencies can take days or weeks for measurements, and ultra high frequencies cannot be measured by existing instruments. The modulus data can then be shifted horizontally along the abscissa to overlap forming a smooth curve. This approach allows the generation of master curves of modulus data spanning considerably wider ranges of time (frequency) and/or temperature than the range of the original data (see figure 2). Discovery流變儀