The polymer electrolytes based on chitosan and ammonium acetate (CH3COONH4) were prepared by solution casting technique and the properties were studied. With the addition of CH3COONH4, the amorphous nature of the polymer electrolytes was promoted. The glass transition temperature, activation energy, and conductivity are closely related. Lower the glass transition temperature, lower the activation energy, higher the conductivity. The 40 wt % ammonium acetate doped polymer electrolyte has the lowest glass transition temperature of 369 K, the lowest activation energy of 0.19 eV, and the highest ionic conductivity of 2.87 x 10(-4) S cm(-1) at room temperature. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 549-554, 2009