Abstract: Chemorheologically viscosity tailored matrix resin formulations for use in forming prepregs and composite articles are disclosed. These formulations have a specified viscosity profile obtained from a curable matrix resin and an effective amount of a reactive resin curing agent reactive at room temperature and a latent resin curing agent substantially nonreactive at room temperature. The latent resin curing agent is activated upon heating or radiation. The matrix resin formulation is adapted upon formulation to have a viscosity sufficiently low enough to enable the matrix resin to impregnate fibers or broadgoods at room temperature without the necessity for the application of heat or solvent and which, upon standing at room temperature after impregnation into the fibers or broadgoods to form a prepreg composition, rises in viscosity.