Polymer, process for producing the polymer, and curable composition containing the polymer

A vinyl polymer having, at a molecular chain terminus, a structure represented by the general formula 1:

• wherein R3 is a hydroxy, amino, epoxy, carboxylic acid ester, ether, amide or silyl group, a group represented by the general formula 2:
• in which R4 represents a hydrogen atom or a methyl group, or a polymerizable olefin-free organic group containing 1 to 20 carbon atoms,
• R1 is a divalent hydrocarbon group containing 1 to 20 carbon atoms or a group having a structure represented by the general formula 3:
• in which R5 is an oxygen atom, a nitrogen atom or an organic group containing 1 to 20 carbon atoms, R6 is a hydrogen atom or a methyl group and each may be the same or different, and when R3 is a group represented by the general formula 2, R1 is —(CH2)n—, —CH(CH3)—, —CH(CH2CH3)—, —C(CH3)2—, —C(CH3)(CH2CH3)—, —C(CH2CH3)2— or —CH2CH(CH3)—, wherein n is an integer of 1 to 20.
• and R2 is a hydrogen atom or a methyl group and X is a halogen atom, a nitroxide or sulfide group or a cobalt porphyrin complex.