The equilibrium state of polyethylene melt was studied by examining the effects of Tmeltand tmelton the long period of B melt melt quenched polyethylene. The long period was found to be proportional to M−½and to depend on Tmeltwith a temperature coefficient α = −0.5 × 10−3. When the melt temperature was changed from one to the other, a relaxation time (3 to 5.5 min) was determined based on long-period measurements. In addition, the relaxation time was found to be proportional to for polydisperse linear polyethylenes. These findings, long relaxation time and the M−3.3dependency, are discussed in light of current crystallization mechanisms and origins of the M−3.3dependency.