Abstract: This invention is directed to a process for the rapid in-situ curing of polymerizable materials to provide macromolecular networks and articles of manufacture that are “morphology-trapped”; that is, they exhibit a fixed phase morphology and/or molecular orientation that is locked in by the curing step. The process includes the steps of mixing together a dead polymer, a reactive plasticizer and an initiator to give a polymerizable composition; further processing the mixture in order to achieve a desired phase morphology and/or molecular orientation of the polymeric constituents; shaping the polymerizable composition into a desired geometry; and exposing the polymerizable composition to a source of polymerizing energy, without mixing, to give a final product with the desired phase morphology and/or molecular orientation locked in place.