A blend of a macrocyclic polyester oligomer and a polymerization catalyst as a one component ready-to-use material with a long shelf life enables production of parts from macrocyclic polyester oligomers without the modification of existing equipment, thereby reducing time and cost of manufacture while expanding the application of macrocyclic polyester oligomers. In this blend material, the macrocyclic polyester oligomer remains intact in solid state at ambient conditions. Upon melting, the blend material initially forms low viscosity fluid, and then rapidly polymerizes to form high molecular weight polyesters which subsequently solidify to form crystalline polymers. In the case of certain macrocyclic polyester oligomers, for example, poly(1,4-butylene terephthalate), demolding can take place at the polymerization temperature, e.g., at about 180° C. to 200° C., because the resulting polyester polymer solidifies fairly rapidly at that temperature without cooling. In one aspect, the invention generally features a blend material that includes a macrocyclic polyester oligomer, a polymerization catalyst, and optionally, a filler. In another aspect, the invention generally features a process for preparing a blend material. In yet another aspect, the invention features processes such as rotational molding, resin film infusion, pultrusion, resin transfer molding, filament winding, making and using powder-coated or hot melt prepreg, compression molding, and roll wrapping, which use the blend material.