Abstract: The present invention relates to a process for forming robust, uniform, low molecular weight crystalline polyester particles. Such particles are useful for forming higher molecular weight polyesters, for example, by solid-state polymerization. Either conventionally-formed, essentially amorphous, non-molten polyester pellets at ambient temperatures or, alternatively, essentially amorphous molten polyester droplets, can be crystallized by rapidly subjecting the droplets or pellets to a thermal shock according to the process of the present invention.

Abstract: Disclosed herein is a novel crystalline form of low molecular weight poly(ethylene terephthalate). This crystalline form may be produced from molten or glassy low molecular weight poly(ethylene terephthalate) material by means of rapid heat transfer to or from the material. The poly(ethylene terephtalate) composition is suitable for use as a starting material for solid-state polymerization in order to produce polymers of higher molecular weight.