Borate glasses are useful, but not as common as silicate glasses,
tetrahedra are linked at corners and arranged in a disordered manner
similar to the
Ordinary window glass is silicate glass, made from sand and metal
oxides. Because glasses are made up of disorderly snarls of chains
of atoms instead of regular rows in a crystalline lattice, they
do not have a definite melting point.
As the temperature is increased, more of the glass structure is
loosened, and a glass softens and begins to flow; it continues to
flow throughout an appreciable temperature range. We will discuss
silicate glasses in more detail in Chapter 6.
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