Abstract: In a process for the polymerization of unsaturated aromatic hydrocarbons with BF.sub.3 -etherate or BF.sub.3 -phenolate as the polymerization catalyst, the improvement comprising using BF.sub.3 -alcoholates as a co-catalyst.

Abstract: A process for the continuous production of indene resins comprising the steps of continuously pre-heating an indene-containing hydrocarbon mixture, continuously adding a boron trifluoride-adduct catalyst and the pre-heated indene-containing mixture to a reaction tube, continuously isothermally reacting the indene-containing mixture with the catalyst at the temperature of the pre-heated mixture to form an indene-containing resin, continuously decomposing the catalyst, and continuously separating the indene-containing resin from the decomposed catalyst and unreacted substances.