A silicon-containing polytrimethylene homo- or copolyether wherein at least a portion of the polymer end groups are silicon-containing end groups having the formula: --OSi(X)(Y)(Z), where X and Y are groups that are easily displaceable from silicon by reaction with water and/or alcohols, and Z is selected from the group consisting of (a) C.sub.1-C.sub.20 linear or branched alkyl groups, (b) cycloaliphatic groups, (c) aromatic groups, each of (a), (b) and (c) being optionally substituted with a member selected from the group consisting of O, N, P and S, (d) hydrogen, and (e) groups that are easily displaceable from silicon by water and/or alcohol.