a1 Corporate Research Laboratories, Eastman Kodak Company, Rochester, New York 14650
Silicon-29 NMR is used to study the structural intermediates in tetramethyl and tetraethyl orthosilicate (TMOS and TEOS) low pH sol-gel reactions. Differences in the number of compact ring structures are related to differences in gel times. Reactions are followed at various silicon: water: acid molar ratios.
(Received June 02 1988)
(Accepted November 21 1988)