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Optical Glass.
This type of glass is obtained by replacing
calcium oxide with lead oxide. Since the fusing can be obtained
at lower temperatures it allows for considerable energy savings.
Its discoverer, George Ravenscroft, an Englishman, became
aware in the XVII century of the fact that, adding lead oxide
to the traditional formula, a transparent, colourless glass
was obtained.
This type of glass is called lead crystal because of its transparency
and resonance; qualities that endow a very similar appearance
to rock crystal. It shows a thermal coefficient of expansion
of 103, which provides suitable conditions for workmanship,
mostly allowing for highly difficult and beautiful cuts to
be made on its surface to create pieces which today are called
hand cut glass.
Due to its purity and transparency, it has more refraction
and dispersion capabilities; thus, it is also used as optic
glass in eyeglasses, telescopes, microscopes, photographic
cameras and other instruments. Its use in the photographic
field is due to its capability to disperse light in a wide
array of colours, which goes uniformly through the lens to
be captured in the film without variations.
Different types
of glass.
 Lime
Glass
Borosilicate
Glass
Optical
Glass
Tempered
or Safety Glass
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