“…Prior studies on PBT reported changes in the above-mentioned nucleation modes and crystal morphologies . As we reported previously, , the nucleation and growth kinetics also showed characteristic differences in the respective peak regions. Regarding crystallization kinetics, the Avrami model (Kolmogorov–Johnson–Mehl–Avrami, KJMA model), which describes the nucleation and subsequent growth of crystal domains, is applicable. − In the KJMA model, the evolution of total crystallinity, i.e., volume fraction of crystal domains, ϕ over time is expressed by the following equation based on the extended volume concept in terms of an extended volume fraction ϕ 0 , which allows overlap between domains ϕ 0 ( t ) = prefix− ln nobreak0em0.25em ( 1 − ϕ ) Furthermore, ϕ 0 can be expressed by the homogeneous nucleation rate I or the nuclei density of foreign heterogeneities N 0 , and linear growth rate G .…”