Since ancient times, glasses were stained by adding metal compounds to the
melt, most often oxides. Thus, in modern production to receive yellow glass CrO3 is used,
blue — CuO, green — FeO, Fe2O3, olive-brown — V2O3, V2O5, violet and purple — NiO and Mn2O3. Iron compounds are able to give different colors to the glass. Iron oxide
paints glass in blue-green, and in a mixture with coal and sulfur - in orange
color. The color of the glass depends not only on the type of oxide but also on
its quantity. For example, cobalt (II) oxide in small quantities gives blue
glass, and in large quantities - violet-blue. Copper (II) oxide gives blue
color in the sodium-calcium glass, and green in the potassium-zinc glass.
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| Colored Glass |
Dyes not only affect the color of the finished glass but also change,
accelerate the course of physicochemical reactions during glass melting. Thus,
dyes play an important role in the manufacture of glass. In addition to dyes,
mufflers are also used for glass melting. Mufflers are the additives that
increase the dispersion of light in the glass. They can give the effect from
light opal to full milky opacity.
Improving the process of removing and neutralizing unnecessary coloring
impurities in the manufacture of sheet glass allowed manufacturers to announce
the release of "clarified" glass of various brands. Lightened glass
is characterized by the improved color transmission of objects behind the glass
and the greater light transmission.
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| Lightened Glass |
