An electrochromic medium for use in an electrochromic device comprising: at
least one solvent; an anodic electroactive material; a cathodic
electroactive material; wherein at least one of the anodic and cathodic
electroactive materials is electrochromic; and wherein at least one of the
anodic and cathodic electroactive materials is associated with a diffusion
coefficient controlling moiety which serves to lower the diffusion
coefficient of the associated material relative to the same without the
diffusion coefficient controlling moiety.
