A hydrolytic polycondensation reaction of a rigid, rodlike nonmesomorphous precursor leads to an isotropic sol and then an anisotropic birefringent xerogel (see scheme). Optical and X-ray structural analyses demonstrate a short-range order and the possibility of a crystalline order.

The nature of the organic group is a key factor in the organization of the gel prepared by sol−gel polycondensation of (MeO)3Si−R−Si(OMe)3 precursors. Whereas isotropic gels are formed with flexible alkyl R groups, anisotropic gels are formed with rigid aryl organic groups.

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