Published online by Cambridge University Press: 10 February 2011
A model is described which incorporates hydrolysis pseudo-equilibrium to quantify the evolution of silicon site distributions in sol-gel polymerization up to higher conversions than previously possible. 29Si nuclear magnetic resonance spectroscopy data are used 1) to provide a means of recognizing hydrolysis pseudo-equilibrium and 2) to provide examples where different substitution effects on condensation rate coefficients caused by branching are observed. Extension of the model to copolymerization is discussed.