Article having a layer containing a copolymer of glycidyl methacrylate and allyl glycidyl ether

As an article of manufacture, a composite sheet comprising (1) a support;

• and, in surface contact therewith, (2) a radiation-responsive organic-solvent-soluble layer of uniform thickness over part of the surface of said support and an organic solvent-insoluble layer over part of the surface of said support, said layers containing in admixture, a copolymer of glycidyl methacrylate and allyl glycidyl ether, derived from reaction of a mixture consisting essentially of the monomers containing from about a 4 to 5 molar excess of glycidyl methacrylate per mole of allyl glycidyl ether in the presence of a free-radical polymerization catalyst and a solvent at a temperature below about 100.degree. C, said copolymer having an inherent viscosity of at least about 0.25 and an epoxide equivalent of at least about 0.65 per 100 grams of polymer, and as a latent curing catalyst, an aromatic diazonium salt of a complex halogenide which decomposes upon exposure to electromagnetic or electron beam irradiation to release a Lewis Acid effective to initiate polymerization, said catalyst being present in an amount sufficient to effect polymerization of said copolymer and being selected from compounds having the general formula (ArN.sub.2).sub.m (MX.sub.n+m) wherein Ar is an aryl or substituted aryl group;
• X is chlorine or fluorine, M is phosphorous, n is the oxidation state of M, and m is the number of diazonium groups in the diazonium salt as determined by the net charge on the complex anion (MX.sub.n+m).sup.-m ;
• said solvent-soluble layer having had substantially no exposure to irradiation and said solvent-insoluble layer having been exposed to electromagnetic or electron beam irradiation for a period of time sufficient to decompose said catalyst and polymerize said copolymer.