The present disclosure discloses a novel multi-stable and erasable anti-counterfeiting technology with controlled reflection color and the application thereof in optical coding. The method and use are characterized by high thermal stability and robust fatigue resistance, and the realization thereof relies on the material system composed of an intrinsic chiral diarylethene molecule based on steric hindrance ethene bridge and a liquid crystal (LC) material disclosed herein. The diarylethene based on steric hindrance ethene bridge has the following structural feature:

##STR00001##

The material system composed of a diarylethene compound based on steric hindrance ethene bridge and an LC can be prepared by a simple preparation process from cheap raw materials, can achieve a wide spectral color adjustment range, and has excellent thermal stability and fatigue resistance, which is expected to be further widely used in the fields of dual erasable anti-counterfeiting and optical information encoding with high thermal stability and strong fatigue resistance.

The present disclosure discloses a novel multi-stable and erasable anti-counterfeiting technology with controlled reflection color and the application thereof in optical coding. The method and use are characterized by high thermal stability and robust fatigue resistance, and the realization thereof relies on the material system composed of an intrinsic chiral diarylethene molecule based on steric hindrance ethene bridge and a liquid crystal (LC) material disclosed herein. The diarylethene based on steric hindrance ethene bridge has the following structural feature:

##STR00001##

The material system composed of a diarylethene compound based on steric hindrance ethene bridge and an LC can be prepared by a simple preparation process from cheap raw materials, can achieve a wide spectral color adjustment range, and has excellent thermal stability and fatigue resistance, which is expected to be further widely used in the fields of dual erasable anti-counterfeiting and optical information encoding with high thermal stability and strong fatigue resistance.

An object of the present invention is to provide a temperature sensing material that changes a color density continuously with the lapse of time at a temperature not lower or higher than a predetermined temperature and a temperature deviation time estimating system using it. In order to achieve the above object, the temperature sensing material according to the present invention is a temperature sensing material having a structure of dispersing a temperature indicating material that changes color by crystallization in a dispersion medium and is characterized in that an average particle size of the temperature indicating material is not larger than a resolution when observed and a volume fraction of the temperature indicating material to the temperature sensing material is not less than 5% to less than 90%.

A photochromic curable composition comprising a radically polymerizable monomer having at least one oxetanyl group in one molecule, a photochromic compound and radically polymerizable monomers other than the above polymerizable monomer, and a photochromic cured body obtained by polymerizing the photochromic curable composition.

A photochromic curable composition comprising a radically polymerizable monomer having at least one oxetanyl group in one molecule, a photochromic compound and radically polymerizable monomers other than the above polymerizable monomer, and a photochromic cured body obtained by polymerizing the photochromic curable composition.

A thermochromic pigment composition comprising: (A) at least one electron-donor organic dye compound, (B) at least one electron-acceptor compound, and (C) at least one compound. The thermochromic pigment composition is microencapsulated and is useable in writing instruments.

The photochromic compound is represented by general formula (1):

##STR00001## wherein, X denotes an oxygen atom, or a nitrogen atom unsubstituted or substituted by a substituent selected from Y.sup.1 group: —R.sup.1, -A.sup.1(B.sup.1).sub.l(A.sup.2).sub.m(B.sup.2).sub.nR.sup.2, -A.sup.3A.sup.4, -A.sup.5R.sup.3 R.sup.1 denotes a cyano group or the like, R.sup.2 denotes an alkyl group or the like, R.sup.3 denotes a halogen atom or the like, A.sup.1, A.sup.2, A.sup.3, and A.sup.5 each independently denote an alkylene group or the like, A.sup.4 denotes a naphthyl group which may be substituted, B.sup.1 and B.sup.2 each independently denote a divalent group selected from the following group:

##STR00002## l, m, and n are each independently 0 or 1, provided that n is 0 when m is 0, Y.sup.2 denotes a hydrogen atom or the like, R denotes a hydrogen atom or the like, and

##STR00003##

denotes a norbornylidene group, a bicyclo[3.3.1]nonylidene group, or an adamantylidene group which may each be substituted.

The photochromic compound is represented by general formula (1):

##STR00001## wherein, X denotes an oxygen atom, or a nitrogen atom unsubstituted or substituted by a substituent selected from Y.sup.1 group: —R.sup.1, -A.sup.1(B.sup.1).sub.l(A.sup.2).sub.m(B.sup.2).sub.nR.sup.2, -A.sup.3A.sup.4, -A.sup.5R.sup.3 R.sup.1 denotes a cyano group or the like, R.sup.2 denotes an alkyl group or the like, R.sup.3 denotes a halogen atom or the like, A.sup.1, A.sup.2, A.sup.3, and A.sup.5 each independently denote an alkylene group or the like, A.sup.4 denotes a naphthyl group which may be substituted, B.sup.1 and B.sup.2 each independently denote a divalent group selected from the following group:

##STR00002## l, m, and n are each independently 0 or 1, provided that n is 0 when m is 0, Y.sup.2 denotes a hydrogen atom or the like, R denotes a hydrogen atom or the like, and

##STR00003##

denotes a norbornylidene group, a bicyclo[3.3.1]nonylidene group, or an adamantylidene group which may each be substituted.

An object of the present invention is to provide a novel electrochromic device (ECD). Disclosed is an electrochromic device (ECD) comprising two metal-complex-based electrochromic thin films individually acting as a working electrode and a counter electrode; (i) one of the two metal-complex-based electrochromic thin films being a film of a cathodically coloring metallo-supramolecular polymer comprising at least one organic ligand having a plurality of metal coordination positions and a metal ion of at least one transition metal and/or lanthanoid metal with the at least one organic ligand and the metal ion being arranged alternately, and the other of the two metal-complex-based electrochromic thin films being a film of an anodically coloring metal hexacyanoferrate (MHCF) represented by the formula: M(II).sub.3[Fe(III)CN.sub.6].sub.2 (where M=Fe, Ni or Zn), and (ii) the electrochromic device having a first conducting substrate; the film of the cathodically coloring metallo-supramolecular polymer; an electrolyte; the film of the anodically coloring metal hexacyanoferrate (MHCF); and a second conducting substrate being arranged in this order.

An object of the present invention is to provide a novel electrochromic device (ECD). Disclosed is an electrochromic device (ECD) comprising two metal-complex-based electrochromic thin films individually acting as a working electrode and a counter electrode; (i) one of the two metal-complex-based electrochromic thin films being a film of a cathodically coloring metallo-supramolecular polymer comprising at least one organic ligand having a plurality of metal coordination positions and a metal ion of at least one transition metal and/or lanthanoid metal with the at least one organic ligand and the metal ion being arranged alternately, and the other of the two metal-complex-based electrochromic thin films being a film of an anodically coloring metal hexacyanoferrate (MHCF) represented by the formula: M(II).sub.3[Fe(III)CN.sub.6].sub.2 (where M=Fe, Ni or Zn), and (ii) the electrochromic device having a first conducting substrate; the film of the cathodically coloring metallo-supramolecular polymer; an electrolyte; the film of the anodically coloring metal hexacyanoferrate (MHCF); and a second conducting substrate being arranged in this order.