Polymerization rates were proportional to initial Sn(Oct)(2) concentration at low [Sn(Oct)(2)](0)/[PrOH](0) values, but began to level off at higher values. When [Sn(Oct)(2)](0)/[PrOH](0) was significantly greater than unity, the opposite behavior occurred. Tin(H) alkoxide concentration became limited by the initial PrOH concentration and independent of initial Sn(Oct)(2) concentration. Addition of 2-ethylhexanoic acid caused polymerization rate retardation, without affecting molecular weight. A control polymerization was conducted in the absence of PrOH. The molecular weight of the resulting polymer was consistent with the measured water content (3.7 wt % by Karl Fisher titration) of the as-received Sn(Oct)(2). The polymerization rate in the absence of PrOH was slow, and this suggested that water is less efficient than an alcohol in creating polymerization-active stannyl ether bonds. (C) 2004 Wiley Periodicals, Inc.