MODERN GLASS — STOOKEY 



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Figure 2. — Schematic two-dimensional representation according to Zachariasen of structures 

 of Si02 network former: a, crystal; b, glass, 



polymer network, loosely bonded to the silica through oxygen bonds, 

 as shown in figure 3. We can picture the sodium ions as high-tem- 

 perature fish swimming through a three-dimensional net whose 

 meshes become gradually more rigid and smaller in size as the 

 material cools. Such "network modifiers" greatly increase the 

 high-temperature fluidity by breaking some of the silicon-oxygen 

 bonds. 



