The copolymerization of 1

1

5-trihydro-oetafluoro-1-pentyl glycidyl ether with tetrahydrofuran was carried out by use of BF3·O(C2H5)2 as catalyst in the presence of diethylene glycol．The products isolated from the copolymer have been studied by gas chromatography，thin-layer chromatography，IR-，and NMR-spectrometry and have been found to contain a low molecular weight compound having an ethoxy group which is produced due to the presence of small quantity of ether introduced into polymeric system by the catalyst．At the same time，monohydroxylcopolymers with ethoxy group have also been formed．Similar copolymerization were carried out by use of BF3·O(C4H8) instead of BF3·O(C2H5)2，it is found that the monohydroxylcopolymer is less in quantity in the obtained copolymer．