of poly(ether-ester) copolymers were synthesized from poly(2,6 dimethyl-1,4-phenylene oxide) (PPO) and poly(ethylene terephthalate) (PET). The synthesis was carried out by two-step solution polymerization process. PET oligomers were synthesized via glycolysis and subsequently used in the copolymerization reaction. FTIR spectroscopy analysis shows the coexistence of spectral contributions of PPO and PET on the spectra of their ether-ester copolymers. The composition of the poly(ether-ester)s was calculated via H-1 NMR spectroscopy. A single glass transition temperature was detected for all synthesized poly(ether-ester)s. T-g behavior as a function of poly(ether-ester) composition is well represented by the Gordon-Taylor equation. The molar masses of the copolymers synthesized were calculated by viscosimetry.