Glass transition temperatures of raw and filled rubbers can be measured not only statically with dilatometry or differential scanning calorimetry but also dynamically with dynamic viscoelastometry. Introduction of interchain crosslinking shows clear effect to increase the glass transition temperature. This is because chain motion is constrained with crosslinked network. However, mixing of various filler into raw rubber leads to no change in the glass transition temperature irrespective of kind of filler or amount of filler, unless interaction between polymer chain and filler particle is not so strong or amount of filler loaded is not so large. No change in T_g with filler loading may be due to much larger dimension of filler particles in comparison with chain segment size.