The values quoted in MaterialUniverse are measured under ambient conditions (~20°C) and low frequencies (~1Hz). This value is provided to enable you to quickly compare the damping characteristics for all the main material classes.
If you require more in-depth information, then consider using one of the specialist polymer data tables, such as CAMPUS and M-Base Plastics. This data table contains values for dynamic shear modulus at different temperatures, gathered from manufacturers’ datasheets.