In this paper, we prepared two spun-cast PVDF-TrFE/hyperbranched polyester (HBP) blend (90/10 wt.-%) film samples on KBr substrate (Blend-AC sample). One of the AC sample was thermally treated at 130oC (Blend-AN sample). Crystal transition behavior were studied by treating both AC and AN samples to 30→120→30oC cycle by in-situ FTIR spectroscopy under transmission (TS) mode. From qualitative FTIR data, absorption intensity of A1 band at 1289.5 cm-1 for AC and 1292 cm-1 for AN decreased gradually during heating for both the samples. However, it is increased at 30oC condition for AC sample, whereas it reached the initial intensity for AN sample at 30oC condition. Blend-AC and Blend-AN thin film samples exhibit irreversible and reversible phase transitions, respectively. Further, the FTIR-TS heating-cooling data were subjected to Factor Analysis (FA). AN sample exhibited reversible phase transition (70%↔70%), while AC sample displayed irreversible transition (50%↔70%), which signifies the importance of this study.