Reversible coloring/decoloring reaction of leuco dye controlled by long-chain molecule

Leuco dye indicates the reversible coloring reaction with acidic compounds (called developer) having long-chain moiety. In order to clarify the structural change between colored state and decolored one of this system, X-ray diffraction (XRD) measurements and transmission electron microscope (TEM) observations were performed. It was found that mixture of leuco dye and developer took different layered structures between colored and decolored state. This structural change shows intercalation and deintercalation of leuco dye occur in the reversible coloring process. The mechanism of coloring/decoloring reaction of leuco dye with long-chain molecule is proposed.