The kinetics of the polymerization of ethyl glycidyl ether and allyl glycidyl ether with BF3OEt2as catalyst has been studied. Chain transfer to the monomer has been evidenced. It increased with the monomer concentration and decreased with the increase of the dielectric constant of the solvent used and decreased in the presence of a monomer more basic than glycidyl ethers, for example, 1,3-dioxepane.