UV absorption of titanium oxide based gels

A spectroscopic study of the gelation and aging of the titanium oxide based gels has been carried out. A careful analysis of measured spectra has shown a permanent growth of the UV absorption in the spectral range of hν⩾Ethr=3.24 eV during all the period of observations. The absorption saturates at times much longer than the gelation time. The observed kinetics is discussed in terms of short oxo-polymer chains nucleation, formation of the primary gel, and gel mass increase under aging. Simple basic models relating the absorption growth to the accumulation of polymeric units successfully fit the experimental curve. The observations suggest using the UV absorption for control of the gel formation.