As a model for polymers, the pseudocrosslink of various sizes is proposed. The size of links, lengths of connected chains, and the times tau’s for their translation or relaxation are derived. According to the size, four transition temperatures (T’s) are proposed such as the linking for the smallest size A (T-A), that for the largest one B (T-B), the melting point (T-m), and the glass transition point (T-g). The equation for T-g is derived with an assumption that the cooling time t is equal to the relaxation time of the segment at T-g and T-g is found to be about 50 degrees C higher than T-A. T-g decreases with t. T-B is twice as much as T-A. T-g/T-B is 2/3 in the general case and 1/2 for hindered polymers. T-m is very close to T-B, but somewhat lower than it when the cohesion heat is large. Related problems are discussed : The thermal expansion coefficient above T-g is about 1/10 T-g. The rebound resilience of rubber at temperature T is given by a ratio of(T - T-g)/(T - T-A) The sound velocities in glassy plastics and rubber are 2000 and 50-100 m/s, respectively, depending on the elasticity. The temperature-shift factor for the stress-relaxation spectrum is derived directly from the equation for the relaxation time without use of the thermal expansion coefficient.