Living Reference Work Entry

Handbook of Sol-Gel Science and Technology

pp 1-31

Date: Latest Version

Characterization of Sol–Gel Materials by Infrared Spectroscopy

  • Rui M. AlmeidaAffiliated withDepartamento de Engenharia Química / Centro de Química Estrutural (CQE), Instituto Superior Técnico / Universidade de Lisboa Email author 
  • , Ana C. MarquesAffiliated withDepartamento de Engenharia Química / Centre for Natural Resources and the Environment (CERENA), Instituto Superior Técnico, Universidade de Lisboa


Infrared (IR) spectroscopy has been widely used in the characterization of sol–gel (SG) materials, leading to an extensive knowledge of the relationship between IR spectra, atomic level structure and properties of bulk materials, and mainly thin films. Moreover, the development of in situ time-resolved IR spectroscopy has enabled the monitoring of structural changes during physical phenomena occurring in the advanced processing of SG-derived materials. This chapter reviews the various IR spectroscopy techniques which have been used in the study of SG materials, including silica-based inorganic and hybrid gels plus other oxide and non-oxide compositions, with particular emphasis on the relationships between the IR spectra and the presence of OH species, porosity, longitudinal and transverse vibrational mode splittings, and the general problems involved in the densification of SG-derived coatings and bulk materials.