Effects of organic and inorganic network development on the optical properties of ORMOSILs

Abstract

The preparation of organic–inorganic hybrids based on the use of sol–gel chemistry offers a creative approach for synthesizing novel materials. One of the most promising directions for organic–inorganic hybrid materials is in the area of optics. An important consideration is that optical losses from scattering will arise in these materials if separation of the organic and inorganic phases occurs. The difficulties in obtaining such hybrid structures without phase separation is investigated for polymethylmethacrylate based organically modified silicates. Here, three approaches for initiating polymerization reactions of the organic component are reported. The influence of the organic and inorganic network developments is correlated with optical transparency. Tuning organic and inorganic reaction rates is found to be insufficient in overcoming phase separation. The most successful method involved dissolving the sol components in a common solvent before instituting polymerization treatments. Materials synthesized by this approach satisfy three important criteria for organic–inorganic hybrid laser host materials: an optically transparent matrix with little or no phase separation; comparable volume fractions of organic and inorganic components to obtain the benefits of both phases; and a high degree of polymerization reactions within the acrylic phase.