Glass coloring and color marking

Beer bottles of different colors

Glass coloring and color marking may be obtained by in several ways.

  1. by the addition of coloring ions,[1][2]
  2. by precipitation of nanometer sized colloides (so-called striking glasses[1] such as "gold ruby"[3] or red "selenium ruby"),[2]
Ancient Roman enamelled glass , 1st century, Begram Hoard
  1. by colored inclusions (as in milk glass and smoked glass)
  2. by light scattering (as in phase separated glass)[2]
  3. by dichroic coatings (see dichroic glass), or
  4. by colored coatings

Coloring ions[]

Iron(II) oxide glass

Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron oxide impurities produce a green tint which can be viewed in thick pieces or with the aid of scientific instruments. Further metals and metal oxides can be added to glass during its manufacture to change its color which can enhance its aesthetic appeal. Examples of these additives are listed below:

Amber Glass
Uranium glass glowing under UV light
Cobalt glass for decoration

Striking glasses[]

Coloring added to glass[]

The principal methods of this are enamelled glass, essentially a technique for painting patterns or images, used for both glass vessels and on stained glass, and glass paint, typically in black, and silver stain, giving yellows to oranges on stained glass. All of these are fired in a kiln or furnace to fix them, and can be extremely durable when properly applied. This is not true of "cold-painted" glass, using oil paint or other mixtures, which rarely last more than a few centuries.

Colored inclusions[]

Tin oxide with antimony and arsenic oxides produce an opaque white glass (milk glass), first used in Venice to produce an imitation porcelain, very often then painted with enamels. Similarly, some smoked glasses may be based on dark-colored inclusions, but with ionic coloring it is also possible to produce dark colors (see above).

Color caused by scattering[]

The Tyndall effect in opalescent glass: it appears blue from the side, but orange light shines through.[10]
Porous glass pore-size gradient (large pores on the right); coloring based on the Tyndall effect.

Glass containing two or more phases with different refractive indices shows coloring based on the Tyndall effect and explained by the Mie theory, if the dimensions of the phases are similar or larger than the wavelength of visible light. The scattered light is blue and violet as seen in the image, while the transmitted light is yellow and red.

Dichroic glass[]

A pendant made from dichroic glass

Dichroic glass has one or several coatings in the nanometer-range (for example metals, metal oxides, or nitrides) which give the glass dichroic optical properties. Also the blue appearance of some automobile windshields is caused by dichroism.

See also[]

References[]

  1. ^ a b Bernard H. W. S. De Jong, Ruud G. C. Beerkens, Peter A. van Nijnatten: "Glass", in: "Ullmann's Encyclopedia of Industrial Chemistry"; Wiley-VCH Verlag GmbH & Co. KGaA, 2002, doi:10.1002/14356007.a12_365
  2. ^ a b c Werner Vogel: "Glass Chemistry"; Springer-Verlag Berlin and Heidelberg GmbH & Co. K; 2nd revised ion (November 1994), ISBN 3-540-57572-3
  3. ^ Formation of Gold Nanoparticles in Gold Ruby Glass: The influence of Tin
  4. ^ Substances Used in the Making of Coloured Glass Archived 2010-04-02 at the Wayback Machine 1st-glass.1st-things.com (David M Issitt). Retrieved 9 April 2014
  5. ^ Nassau, Kurt (2001). The physics and chemistry of color: the fifteen causes of color. Wiley. ISBN 978-0-471-39106-7. Retrieved 4 April 2013.
  6. ^ Chemical Fact Sheet - Chromium Archived 2017-08-15 at the Wayback Machine www.speclab.com. Retrieved 3 August 2006
  7. ^ a b R. Barbour. "Glassblowing for Laboratory Technicians" (PDF). wiredfreak.com. Archived from the original (PDF) on 26 March 2012. Retrieved 9 April 2014.
  8. ^ Uranium Glass www.glassassociation.org.uk (Barrie Skelcher). Retrieved 3 August 2006
  9. ^ "Selenium". Illustrated Glass Dictionary. www.glassonline.com. Archived from the original on 1 October 2011. Retrieved 9 April 2014.
  10. ^ "Why is the sky blue, and sunsets red?: Blue and Red". Causes of Color. Institute for Dynamic Educational Advancement. Retrieved 23 April 2014.