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In the last few years, the color analysis of the studied surface has been regarded as a nonexpensive way to obtain not only the spectrochemical data but also the spatiotemporal information of the entire surface. Mean color intensities and standard deviation calculated from the red, green, and blue color histograms of digital images of surfaces have been considered particularly useful for the chemical understanding of surface kinetics. The shape of curves, the maximum of peaks, or the halfpeak widths depend on the kinetic constants and on the kinetic order of the surface chemical process. Some strategies used for obtaining the kinetics from RGB color intensities and their standard deviations are proposed.

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Poly(Azure A) (PAA) films doped with sodium dodecyl sulfate (SDS) were grown on transparent indium tin oxide (ITO) glass substrates by cyclic voltammetry. The electrochromism of PAA was investigated by digital video-electrochemistry (DVEC). DVEC consists of the acquisition of sequential digital images during the electro-stimulated changes of PAA color. The evolution of red, green, and blue (R, G, B) colors intensity (I) of analyzed pixels provides enough sensitivity to detect changes of some nmol cm −2 of electroactive centers. Besides, the different time evolution of these color intensities can serve to discern among different electroactive centers activated in the polymer. For the first time, contrast, coloration efficiency, and bleaching times of PAA are calculated by DVEC. The coloration efficiencies were between 15-25 cm 2 mC −1 with short response times for the bleaching process between 2.9 and 5.5 s. PAA has good electrochromic performances to be used in electrochromic devices. Our present work provides an important insight into the design principles for a practical application of DVEC to characterize electrochromic devices in light-controlled conditions allowing us to find the best performances of these materials.