The glass is
painted by introducing some metal oxides into it or the formation of colloidal
particles from certain elements. So, gold and copper in the colloidal
distribution color glass in red. Such glass is called gold or copper ruby,
respectively. Colloidal silver turns the glass yellow. Selenium is a good dye.
In the colloidal state, it paints the glass in pink, and as a CdS • 3CdSe
compound - in red. Such glass is called selenium ruby.
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| Copper Ruby |
When painting
with metal oxides, the color of glass depends on its composition and on the
amount of oxide-dye. For example, cobalt (II) oxide in small quantities gives
blue glass, and in large quantities - violet-blue with a reddish tinge. Copper
(II) oxide in sodium-calcium glass gives a blue color, and in potassium-zinc -
green. Manganese oxide (P) in sodium-calcium glass gives a red-violet color,
and in potassium-zinc - blue-violet. Lead oxide (II) enhances the color of the
glass and gives the color a bright tone.
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| Bottle Glass |
Low-grade bottle
glass, as a rule, has a color that depends on the presence of Fe2+ and Fe3+
ions in it. Glass raw materials are difficult to purify from iron ions and
therefore they are always present in cheap varieties. Fe2+ ions absorb light
rays with a wavelength of about 600 microns (yellow and red) and, therefore,
paint the glass in an additional blue color. Fe3+ ions absorb rays with a
wavelength of 500 μm (blue and violet), painting the glass in a yellowish
color. It is important to note that Fe2+ ions in the visible light region have
a specific absorption, about 10 times greater than Fe3+ ions. Since the glass
simultaneously contains both Fe2+ ions and Fe3+ ions, together they give the
glass a greenish color (bottle color).
