Abstract: A rewritable photochromic optical disk comprises a photochromic recording layer made of a dibenzothienyl ethene derivative, 1,2-di(2-cyano-3-benzothienyl)-1,2-dicyanoethene capable of assuming first and second states, the first state with a first absorption band transforming into the second state with a second absorption band by irradiating a first light beam of a first wavelength, and the second state transforming into the first state by irradiating a second light beam of a second wavelength in the second absorption band. This rewritable photochromic optical disk has a stability in the repeated recording and erasing information and a high thermal stability and capable of storage of information extended over a long period of time, in accordance with its higher quantum yield than that of the conventional dibenzothienyl ethene derivative so that the achromatic reaction takes place by irradiation of a low power laser beam.

Abstract: A novel skin-whitening composition comprising as an active ingredient a compound of the formula: ##STR1## useful for the prophylaxis and treatment of skin troubles due to melanin metabolism disorder.

Abstract: Styryl-like compounds showing improved stability and prolonged lifetime on repetition of the coloration and bleaching cycle and represented by the general formula ##STR1## in which R represents an alkyl or phenyl group, R.sub.1 and R.sub.2 independently represent a lower alkyl group, a hydroxyalkyl group, or an alkoxyalkyl group, R.sub.3 represents hydrogen, an alkyl group, a halogen, a nitrile group, an aromatic group or a phenoxy group, Y represents O or S, Z represents an alkylene radical of 2 to 4 carbon atoms, with or without alkyl substituent(s), necessary for forming a ring structure together with ##STR2## A represents a residue of an aromatic aldehyde, a heterocyclic aldehyde, an aromatic nitroso compound or a heterocyclic nitroso compound, and n is an integer of 2 or 3.

Abstract: This invention relates to color-changing stryl-like compounds and the preparing of the same. A compound according to the present invention has, as its principal ring, an indoline ring of 2nd position, and has, at stimulation reversible or irreversible change(s) between a closed ring structre of a non-plane molecular structure indicated by the following chemical formula(1) showing white or pale color, and an open ring structure of a plane molecular structure indicated by the following chemical formula(2) showing vivid visible color: ##STR1## Wherein Q represents benzene ring with or without substituted radicals and/or condensed ring(s); R.sub.1 and R.sub.2 represent lower alkyl radicals hydroxyalkyl radicals or alkoxyalkyl radicals of the same or different kinds,; R.sub.

Abstract: This invention relates to color-changing styryl-like compounds and the preparing of the same. A compound according to the present invention has, as its principal ring, an indoline ring of 2nd position, and has, at stimulation reversible or irreversible change(s) between a closed ring structure of a non-plane molecular structure indicated by the following chemical formula(1) showing white or pale color, and an open ring structure of a plane molecular structure indicated by the following chemical formula(2) showing vivid visible color: ##STR1## wherein Q, R.sub.1, R.sub.2, R.sub.3, Y, Z, A and X are defined in the detailed specification.

Abstract: This invention relates to an apparatus for changing color utilizing new materials, the color of which changes, disappears or appears at the stimulation by, for example, light, heat, ions, electricity, pressure or radioactive rays. The materials are new styryl-like compounds having the below mentioned chemical formula: ##STR1## Wherein Q represents a benzene ring with or without substituted radicals and/or condensed ring(s); R.sub.1 and R.sub.2 represent lower alkyl radicals, hydroxyalkyl radicals or alkoxyalkyl radicals of the same or different kinds,; R.sub.