Photochromic monomers, photochromic polymers based on the same, photochromic recording media comprising the photochromic polymers, and 3D read/write optical memory comprising the recording media

A photochromic monomer of the general formula (II):

• wherein:
• X is CH2, O, S or N-Alk;
• Y is O, S, or N-Alk;
• n is any integer of 0˜6;
• each of the substituents Q is independently selected from below,
• Alk is a C1-10 alkyl group.

A photochromic polymer having a structural unit in a main chain or as a side chain derived from photochromic monomers of the general formula (I):

• wherein:
• each of the substituents Q is independently selected from below,
• Alk is a C1-10 alkyl group;
• and
• X is Cl, Br, I, F, NH2, CH2OH, CH2Cl, CH2Br, CHO, or COOH.

A photochromic polymer having in a main chain a structural unit of the general formula (IXa):

• wherein:
• X is CH2, O, S or N-Alk;
• Y is O, S, or N-Alk;
• n is any integer of 0˜6;
• each of the substituents Q is independently selected from below,
• Alk is a C1-10 alkyl group.

A photochromic monomer comprising the general formula (I), the general formula (II), or the generally formula (III), wherein:

• the general formula (I) is
• within the general formula (I),
• each of the substituents' Q is independently selected from
• Alk is a C1-10 alkyl group, and
• X is Cl, Br, I, F, NH2, CH2OH, CH2Cl, CH2Br, CHO, or COOH,
• the general formula (II) is
• within the general formula (II),
• X is CH2, O, S or N-Alk, Y being O, S, or N-Alk,
• n is any integer of 0˜6,
• each of the substituents Q is independently selected from below,
• and
• Alk is a C1-10 alkyl group, and
• the general formula (III) is
• within the general formula (III), Alk is a C1-10 alkyl group.

A photochromic polymer having a structural unit in a main chain or as a side chain derived from photochromic monomers of the general formula (I), a structural unit in a main chain of the general formula (IXa), or a structural unit in a main chain of the general formula (III′),

• wherein:
• the general formula (I) is:
• within the general formula (I),
• each of the substituents Q is independently selected from below,
• Alk is a C1-10 alkyl group, and
• X is Cl, Br, I, F, NH2, CH2OH, CH2Cl, CH2Br, CHO, or COOH,
• the general formula (IXa) is:
• within the general formula (IXa),
• X is CH2, O, S or N-Alk;
• Y is O, S, or N-Alk,
• n is any integer of 0˜6,
• each of the substituents Q is independently selected from below,
• and
• Alk is a C1-10 alkyl group, the general formula (III′) is:
• Alk is a C1-10 alkyl group.