In situ SHG investigation on the gelation process of organic doped silica film

✍ Scribed by Liying Liu; Lei Xu; Zhanjia Hou; Zhiling Xu; Jie Chen; Wencheng Wang; Fuming Li

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 196 KB
• Volume: 262
• Category: Article
• ISSN: 0375-9601
• DOI: 10.1016/s0375-9601(99)00558-7

✦ Synopsis

The gelation process of organic doped silica film fabricated by the sol-gel technique was investigated by in-situ second Ž . harmonic generation SHG measurements. The SH signal came from the doped hemicyanine molecules which automatically oriented in the film at or near the film-substrate interface. We found that film shrinkage during gelation resulted in disordering of the doped hemicyanine molecules, so the SH intensity decreased during annealing. Thus, the SHG measurement can be used as a semi-quantitative probe of the gelation process in that particular region, which was hard to detect using conventional methods. We found that the time for gelation depends sensitively on the annealing temperatures. The activation energy of the gelling process was obtained from the SHG relaxation measurement. In addition, aggregated hemicyanine molecules dissociated with increasing annealing temperature.