Abstract: A novel polyaddition copolymer having repetition units represented by the following general formula: ##STR1## where R: a lower alkyl group, Ar: a bisphenol compound residue, and X: a CH.sub.2 O group or a COO group, is obtained by copolymerization reaction of a bisoxetane compound represented by the following general formula: ##STR2## and a bisphenol compound.

Abstract: A curable composition comprising a polyfunctional oxetane compound and a polyphenol compound or phenol resin, where a quaternary onium salt or Crown ether compound is preferably further contained as a curing catalyst, provides a novel use for reactions of the oxetane compound as a 4-membered cyclic ether compound.

Abstract: Disclosed is a curable composition comprising (A) an imidazole derivative represented by the following general formula (1), which is capable of generating free imidazole by exposure to light, and (B) a polyfunctional epoxy compound: ##STR1## wherein R represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyl group, a nitro group, a cyano group, an alkoxyl group, a phenoxy group, or an aromatic ring residue capable of forming a condensed ring in combination with a benzene ring. The composition may further incorporate therein at least one compound selected from the group consisting of polyfunctional phenol compounds, polyfunctional carboxylic acids, acid anhydrides, and amine compounds.

Abstract: A photocurable composition comprising the reaction product of the addition compound obtained from an epoxy resin and a photopolymerizable .alpha..beta.-unsaturated carboxylic acid, and a dibasic acid anhydride; a photopolymerizable monomer; and a photopolymerization initiator. The composition is used for making a relief image.