Electrochromic films 1 and 2 based on poly(o-anisidine) and poly(o-anisidine-co-o-nitroaniline) were prepared by cyclic voltammetry method, respectively. The physical properties of the films were studied by UV-Vis, spectrophotometer and field-emission scanning electron microscopy (SEM). The results indicate that the film 1 has two obviously different colors as aqua (U＝－0.5 V) and lavender (U＝0.9 V) under different voltages and its respond time is 15 s, the biggest different transmittance (DT_max) of film 1 is 10% (around 500 nm). The film 2 also has two obviously different colors as olive green (U＝－0.9 V) and deep phthalocyanine blue (U＝1.4 V) under different voltages and the response time is 2 s, the biggest different transmittance (DT_max) of the film 2 is 20% (around 497 nm). From the SEM results, it could be seen that the surface morphologies and the conducting properties of the film 2 are obviously different under the different color states. Based on above results, it can be seen that the film 2 has faster respond time and higher color contrast comparing with those of film 1, so the film 2 is a better electrochromic film.

Key words: electrochromism, electrodeposition, copolymerization, o-anisidine, o-nitroaniline