Photo-induced phase transition organic material

A photo-induced phase transition organic material composed of a diheteroarylethene compound within which photochromic reaction occurs in a crystalline state, said diheteroarylethene compound being expressed by a following general formula I:

• where substituents A and B are selected such that “A” expresses a substituent (i) or (ii), “R1” expresses an alkyl group, an alkoxyl group, a halogen atom, a trifluoromethyl group, a cyano group, or an aryl group which may have at least one substituent;
• “R2” and “R3” express a hydrogen atom, an alkyl group, an alkoxyl group, a halogen atom, a trifluoromethyl group, a cyano group, or an aryl group which may have at least one substituent, respectively, wherein “R2” and “R3” are independent of each other;
• or “R2” and “R3” are bonded to be a carbocyclic ring which may have at least one substituent, or a heterocyclic ring which may have at least one substituent;
• “Y” expresses —O—, —S—, or —NR4— in which “R4” expresses a hydrogen atom, an alkyl group which may have at least one substituent, an aryl group which may have at least one substituent, or a cycloalkyl group which may have at least one substituent;
• and “B” expresses a substituent (iii) or (iv), “R5” expresses an alkyl group, an alkoxyl group, a halogen atom, or a trifluoromethyl group;
• “R6” and “R7” express a hydrogen atom, an alkyl group, an alkoxyl group, a halogen atom, a trifluoromethyl group, a cyano group, or an aryl group which may have at least one substituent, respectively, wherein “R6” and “R7” are independent of each other;
• or “R6” and “R7” are bonded to be carbocyclic ring which may have at least one substituent, or a heterocyclic ring which may have at least one substituent;
• “Z” expresses —O—, —S—, or —NR4— in which “R4” expresses a hydrogen atom, an alkyl group which may have at least one substituent, an aryl group which may have at least one substituent, or a cycloalkyl group which may have at least one substituent.