The copolymers obtained by the spontaneous reaction between 2-phenyl-2-xazoline (PhOx) and different anhydrides (succinic - SA, maleic - MA and phthalic - PA) in the absence of an added initiator have been studied. The copolymers were characterized by FTIR and C-13-NMR spectroscopies. Compositions were determined by quantitative elemental analysis and average molecular weights were obtained by GPC. The PhOx/MA and PhOx/PA were found to be alternating copolymers, whereas the PhOx/SA copolymer was a statistical one, rich in PhOx.