Development of new high transparent hybrid organic-inorganic monoliths with surface engraved diffraction pattern.

In this work, we report on the preparation and optical, thermal and morphological characterization of flexible and transparent hybrid gel materials by sol-gel process. The material synthesis was performed using two different derived siloxanes (3-isocyanate propyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane) and two polyether chains with diamine terminal groups with different molecular weight. Xerogels exhibiting high optical transparency up to 90%, low shrinkage down to 5.5% and average roughness of about 0.3nm were obtained. The optimization of physical and chemical properties made possible to reproduce diffraction gratings with a well-defined pattern by using the molding method. Complementary study of thermal properties revealed that obtained xerogels show to be stable up to 200 ºC. The study of the diffraction characteristics of the obtained grating revealed a good reproducibility of the imprinted grating similar to the original mold. The developed methodology shows potentialities to the production of diffraction lenses with variable and a wide range of formsProject PTDC/QUI/70063/2006 financed by Portuguese Foundation for Science and Technology (FCT)