Indentation stress relaxation of sol–gel-derived organic/inorganic hybrid coating

The indentation stress relaxation is examined of sol–gel-derived phenylsilsesquioxane film coated on a soda-lime glass plate. The rheological transition associated with the condensation reactions from the sol (liquid) to the gel (solid) is elucidated in indentation load relaxation tests. The effects of the heat-treatment-temperature and the heat-treatment-time on the process of gelation (the solidification process) are studied. The change in the chemical structures and the evolution of siloxane networks are discussed in terms of the Fourier transform infrared-spectra (FTIR-spectra) combined with the corresponding rheological transition of the coatings during the condensation processes.