We further monitored the evolution of phase transition of PPC15, PPC10, and PPC5 films by both SAXS and WAXS in situ during the heating-cooling process. Figure shows the SAXS pattern of PPC15 film in a heating-cooling cycle from 30 to 55 o C and backwards. Figure shows little change of diffraction peaks at q = 0.15, 0.23 and 0.26 Å -1 during the increase of the temperature from 30 to 50 ℃. But all the three peaks disappeared when the film was heated to 55 o C. After being cooled down to 30 o C, the SAXS pattern recovered.