Abstract
The oxide film grown on a rhodium metal substrate in alkaline solutions by potential multipulsing behaves as a fast two‐color electrochromic system. Reversible yellow ⇄ dark green or yellow ⇄ brown‐purple coloration changes are obtained in either solutions. The films suffer very small charge losses after 105 cycles in either electrolytes. The response is faster, but the open‐circuit memory is shorter in the more concentrated alkaline solution. The response time of the Rh oxide film in alkaline solutions is comparable to that of the Ir oxide electrochromic in acid solutions, but the open‐circuit memory is longer in the latter system. A loss of electrochromic activity was found to be caused in both rhodium and iridium oxide films by excessive cathodic pulse potentials.