A series of oligoesters was synthesized via the transesterification of dimethyl isophthalate with neopentyl glycol or tetraethylene glycol and the esterification of adipic acid with neopentyl glycol or tetraethylene glycol under diol/diester or diol/diacid molar ratios sufficient to limit molecular weight increasing. These oligoesters were used to depolymerize poly(ethylene terephthalate) (PET) in the presence of zinc acetate to yield new types of glycolysates. The oligoesters and the glycolysates are characterized by H-1 NMR, size exclusion chromatography (SEC). differential scanning calorimetry (DSC), thermogravimetric analyses and matrix assisted laser desorptionlionisation time of flight mass spectrometry (MALDI-TOF MS). These analyses revealed the structure of the different glycolysates. (c) 2005 Elsevier Ltd. All rights reserved.