Thermochromic colour-memory composition

摘要

Thermochromic color-memory compositions exhibiting high color contrast between colored and decolored states with high freedom of selection of the reaction medium, and useful as thermochromic materials, comprise homogeneous solubilized mixtures of (a) an electron-donating color-developing organic compound; (b) an electron-accepting compound; and (c) a reaction medium for controlling the reaction of component (a) with component (b), selected from aliphatic ketones having 10 to 22 carbon atoms and aryl alkyl ketones having 12 to 24 carbon atoms, the composition having a color change hysteresis width ( DELTA H) of 8 to 80 DEG C.