Dense glass

The formation of pure inorganic materials by the sol-gel route requires heating dense glasses can be prepared around Tg ceramic... 

In the sol-gel process, ceramic polymer precursors are formed in solution at ambient temperature shaped by casting, film formation, or fiber drawing and then consolidated to furnish dense glasses or polycrystalline ceramics. The most common sol-gel procedures involve alkoxides of silicon, boron, titanium, and aluminum. In alcohol water solution, the alkoxide groups are removed stepwise by hydrolysis under acidic or basic catalysis and... 

Figure 24-2 Change in wavelength as radiation passes from air into a dense glass and back to air. Note that the wavelength shortens by nearly 200 nm, or more than 30%, as it passes into glass a reverse change occurs as the radiation again enters air.

Heiber at. al. investigated the extrusion of commercial silicon dioxide nanopower using a mixture of polyethylene and wax [Hei 04], With this thermoplastic binder system, powder loadings up to 58 vol% were achieved. With this very high powder loading it was possible to achieve dense glass fibers after sintering at 1100°C. 

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