Two-photon absorbing polymerization method, two-photon absorbing optical recording material and two-photon absorbing optical recording method

A two-photon absorbing polymerization method comprising:

• a first step of irradiating light on a composition comprising a cationic or anionic polymerizable compound capable of a two-photon absorption to form only a latent image;
• and a second step of exciting the latent image by an irradiation of light to cause a polymerization,
• wherein as a two-photon absorbing compound, a cyanine dye, a merocyanine dye, an oxonol dye, a phthalocyanine dye or a compound represented by the following formula (1) is used:
• wherein R1, R2, R3 and R4 each independently represents a hydrogen atom or a substituent and some of R1, R2, R3 and R4 may combine with each other to form a ring;
• n and m each independently represents an integer of 0 to 4 and when n and m each is 2 or more, multiple R1s, R2s, R3s or R4s may be the same or different, provided that n and m are not 0 at the same time;
• and X1 and X2 each independently represents an aryl group, a heterocyclic group or a group represented by formula (2):
• wherein R5 represents a hydrogen atom or a substituent, R6 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and Z1 represents an atomic group for forming a 5- or 6-membered ring.

A two-photon absorbing optical recording method comprising:

• a first step of forming a latent image of a color-forming material comprising a cationic or anionic polymerizable compound by a two-photon absorption;
• a second step of irradiating light on said latent image of a color-forming material to cause a polymerization based on a linear absorption of the color-forming material;
• and thereby forming difference in the refractive index to perform a recording,
• wherein as a two-photon absorbing compound, a cyanine dye, a merocyanine dye, an oxonol dye, a phthalocyanine dye or a compound represented by the following formula (1) is used:
• wherein R1, R2, R3 and R4 each independently represents a hydrogen atom or a substituent and some of R1, R2, R3 and R4 may combine with each other to form a ring;
• n and m each independently represents an integer of 0 to 4 and when n and m each is 2 or more, multiple R1s, R1s, R3s or R4s may be the same or different, provided that n and m are not 0 at the same time;
• and X1 and X2 each independently represents an aryl group, a heterocyclic group or a group represented by formula (2):
• wherein R5 represents a hydrogen atom or a substituent, R6 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and Z1 represents an atomic group for forming a 5- or 6-membered ring.

A two-photon absorbing optical recording method comprising:

• a first step of forming a latent image of a color-forming material containing a cationic or anionic polymerizable compound by a two-photon absorption;
• a second step of irradiating light on said latent image of a color-forming material to cause a polymerization based on a linear absorption of the color-forming material;
• and thereby forming difference in the refractive index to perform a recording, wherein the recording is performed by using a two-photon absorbing optical recording material comprising:
• 1) a two-photon absorbing compound capable of undergoing a two-photon absorption to produce an excited state upon irradiation with light having a wavelength that is longer than the linear absorption band of the compound 1) itself and has a molar absorption coefficient of linear absorption of 10 or less;
• 2) a dye precursor having an absorption shifted to the longer wavelength side than in the original state by electron or energy transfer from said two-photon absorbing compound 1) in the excited state to become a color-forming material having an absorption in the wavelength region where the molar absorption coefficient of linear absorption in the two-photon absorbing compound 1) is 5,000 or less;
• 3) a polymerization initiator capable of initiating a polymerization of a polymerizable compound by electron or energy transfer from said two-photon absorbing compound 1) in the excited state;
• 4) a cationic or anionic polymerizable compound;
• and
• 5) a binder,
• wherein said two-photon absorbing compound is a cyanine dye, a merocyanine dye, an oxonol dye, a phthalocyanine dye or a compound represented by the following formula (1):
• wherein R1, R2, R3 and R4 each independently represents a hydrogen atom or a substituent and some of R1, R2, R3 and R4 may combine with each other to form a ring;
• n and m each independently represents an integer of 0 to 4 and when n and m each is 2 or more, multiple R1s, R2s, R3s or R4s may be the same or different, provided that n and m are not 0 at the same time;
• and X1 and X2 each independently represents an aryl group, a heterocyclic group or a group represented by formula (2):
• wherein R5 represents a hydrogen atom or a substituent, R6 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and Z1 represents an atomic group for forming a 5- or 6-membered ring.

A three-dimensional optical recording method comprising:

• irradiating a two-photon absorbing polymerizable composition with laser light at a wavelength being longer than the linear absorption band of the two-photon absorbing compound and having no linear absorption to induce a two-photon absorption;
• causing photopolymerization by utilizing the two-photon absorption induced to cause a non-uniformity of the compositional ratio of the polymerizable compound and a polymerization reaction product thereof to the binder between the laser-focused area and unfocused area;
• and
• performing a recording by using a three-dimensional modulation of refractive index caused by the non-uniformity of the compositional ratio,
• wherein the two-photon absorbing polymerizable composition comprises a two-photon absorbing compound, a polymerization initiator, a cationic or anionic polymerizable compound and a binder, in which the two-photon absorbing polymerizable composition is capable of generating a three-dimensional modulation of refractive index as a result of photo-polymerization caused by non-resonant two-photon absorption, and said two-photon absorbing compound is a methine dye, a cyanine dye, a merocyanine dye, an oxonol dye, or a phthalocyanine dye.