We have deposited Aluminium on the three types of polycarbonates (PC). The first is the unmodified PC and the second and the third are modified ones which are deposited $SiO_x$ by plasma enhanced chemical vapor deposition (PECVD) with $SiH_4$ and $SiO_2$ by rf magnetron sputtering of quartz plate, respectively. We have succeeded in it except on the first unmodified PC, from which carbon seemed to come up during Aluminium coating. As a result of experiment, the third is the most proper substrate for Al coating with good reproducibility, which also showed $\sim 73\%$ reflectance. We have also coated ITO on the third type of PC by rf magnetron sputtering with varying the partial pressure of oxygen gas. It showed rather low resistivity ($\sim \times 10^{-3}\; \Omega cm$) with $O_2$ partial pressure of $1 \sim 5\times10^{-5}$ Torr. For the understanding of the basic mechanism of electrochromism, we measured the transmittance of amorphous $WO_3$ with He-Ne laser under constant current and the current drop under constant voltage as coloring and bleaching of it. From the result, we conclude that the speed of bleaching is faster than that of coloring. We also measured the transmittance of electrochromic multilayer, changing polarity of applied voltage(1V). The difference between transmitted intensity of coloring and that of bleaching was somewhat small, which was less than $\sim 10\%$ of the transmitted intensity of the fabricated film under no applied voltage. The response time was very slow. And the cycle of coloring and bleaching continued for $\sim 3$ hours. All the experiments above are basic works for fabricating electrochromic systems (mirror, window, display device, etc.) with transparent plastics.
