Low molecular weight (MW) polystyrenes were synthesized by radical polymerization in the presence of catalytic chain-transfer agents. Synthetic conditions are controlled to produce molecules containing one methyl group at one end as well as a double bond at the other end, capped with a phenyl group. Individual oligomers were separated by liquid chromatography, and the properties were analyzed using NMR, ultraviolet-visible (UV-vis) spectroscopy, and size exclusion chromatography with light scattering. The UV-vis spectra, proton NMR spectra, and differential refractive-index increments exhibit an MW dependence of up to six-eight monomer units. The obtained dependencies can be used for precise characterization of the molecular weight distribution of polystyrene obtained by catalytic chain transfer. The double-bonded end groups were found to be exclusively in the transconfiguration for all oligomers. (C) 2001 John Wiley & Sons, Inc.