The solid polymer electrolyte film is prepared using polyvinyl alcohol and alum by the reactive blending method. Different wt% of alum is used for the preparation of the films. Temperature dependent properties of the films were characterized by IR, A/C conductivity, dielectric, conductance, DSC and TGA. The X-ray diffraction pattern of the synthesized film showed an increased crystallinity over pure PVA. The constituent present in the polymer film is found out by EDX measurement. The spin state in which metals present in the film is found out by XPS analysis. The thermal stability of the film is increased over pure PVA. The tensile curve of the polymer sample contains 0.15 wt% of alum showed a strain induced crystallisation behavior due to plasticizing effect of the embedded salt. The polymer sample contains 0.15 wt% of alum showed conductivity (AC) of 1.73 × 10−4 S cm−1. Conduction pattern is studied by dielectric loss experiments.