Radiation absorbing polymer and synthesis thereof

A radiation absorbing polymer which absorbs radiation with wavelength in the range of 180 nm to 450 nm, comprising at least a recurring unit as represented by formula 1 and a recurring unit as represented by formula 2;

• wherein
• R1 and R2 represent independently a hydrogen atom, or an alkyl group;
• X is absent, or represents a methylene group, a linear alkyl group of at least 2 carbon atoms, or branched or cyclic alkylene group with at least 3 carbon atoms,
• Ar is an organic chromophore that absorbs radiation with wavelength in the range of 180 nm to 450 nm and represents a substituted or non-substituted benzene ring, a heterocyclic ring or a condensed ring which is bonded to X directly or through an oxygen atom or a sulfur atom;
• and n is 0 or an integer of 1,
• wherein
• R3 and R4 represent independently a hydrogen atom, an alkyl group, or a carboxyl group;
• and Y represents a hydrogen atom, a substituted or non-substituted alkoxyl group, a substituted or non-substituted alkyl group, a substituted carbonyl group, a substituted or non-substituted oxycarbonyl group or a substituted or non-substituted phenyl group;
• wherein said polymer is obtained by reacting the copolymer comprising at least a recurring unit as represented in formula 3 or 3′ and a recurring unit as represented by formula 2, with a compound as represented by formula 4 which absorbs a radiation with wavelength in the range of 180 nm 450 nm;
• wherein
• R1 and R2 are as defined above;
• wherein
• R3 and R4 and Y are defined above;
• Ar—X—OH (4)
• wherein
• X and Ar are as defined above.