Tin doped silica by sol-gel method: doping effects on the SiO2 Raman spectrum

Glasses of Sn-doped SiO2 were obtainted by the sol-gel method from two diff erent Sn precursors, Sn(OtBu)(4) and Sn(OOCCH3)(2)(C4H9)(2) Structural modi fications from xerogel to glass were monitored by Raman spectroscopy at dif ferent steps of the condensation process. The shifts of the SiO2 intrinsic vibrational modes show that Sn-doping can influence the structural properti es of SiO2 even at relatively low tin concentrations. The changes depend on the thermal treatment and the preparation method. It is suggested that the formation of the SiO2 network is affected by the tin doping process during the early stages of the condensation. (C) 1998 Published by Elsevier Scien ce Ltd.