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Soda-Lime Float Glass

Economically priced sight-glass grade material

Special Properties

  • Low-cost flat-glass
  • Clear transparency under normal lighting conditions
  • Reasonable hardness
  • Moderately chemically resistant

Typical Applications

  • Sight-glass windows
  • Simple front windows
  • Mechanical glass parts
  • Protective glasses
  • Thin sight-glasses

Related glass types

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Soda-lime float glass for sight glass applications

Soda-lime-silica float glass materials with sight glass quality are ideal for all applications that don't require the highest quality surfaces or a high flatness and material purity. The glass consists of about 71 % silica. To lower glass-transition temperature, sodium carbonate ("soda") is added, increasing the glass's water-solubility. Chemical durability is partially gained back by adding calcium oxide ("lime"), magnesium oxide, and aluminum oxide. The result is a low-cost glass with a lowered melting temperature, which can efficiently be processed and is suitable for all commercial applications with moderate requirements.

When looking with the naked eye, the glass has a high-quality appearance, and there are no significant defects or inhomogeneities in the material when looking through it.

However, this type of soda-lime-silica glass material does not achieve our iron-reduced selected float glass's excellent surface quality and flatness, and its physical purity is not as high. For example, a slight grey haze can become visible under intense inspection light with soda-lime glass with sight glass quality. However, this effect is not perceived under normal lighting conditions and has almost no impact on the transmission. About 90 % of visible light is still transmitted, only 1 % less than our selected float glass materials offer.

Our low-cost soda-lime sight glass has the ideal properties for less sophisticated applications like glass covers, simple front windows, sight glasses, or protection glasses. It is a low-cost material used for all non-optics applications that do not need a high chemical or heat resistance and do not require withstanding an increased operating temperature.


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Due to soda-lime glass materials' properties, we don't recommend using them at a high thermal load or in harsh chemical environments. If you search for a glass type with excellent chemical properties and increased temperature resistance, please look at our borosilicate glass datasheet.





Standard Thicknesses

(Please click on a glass thickness to request a quote)

Thickness (mm)


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1,0 ±0,1
2,0 ±0,2
3,0 ±0,3

Refractive Index

  • Approx. 1,52

Mechanical Density

  • Approx. 2,5 g/cm3

Coefficient of Thermal Expansion

  • Approx. 87 × 10-6/K

Typical Glass Composition of Soda-Lime Glass*

  • SiO2 : 71 %
  • Na2O + K2O : 14 %
  • CaO : 8,6 %
  • MgO : 4,4 %
  • Al2O3 : 1,3 %
  • Fe2O3 : 0,1 %
  • SO3 : 0,3 %

*The glass composition can fluctuate from batch to batch. The percentages given are only typical averages and therefore do not add up to exactly 100 %. Since soda-lime-silica float glass is not an optics-grade glass, all specifications above are subject to inevitable fluctuations. Therefore, all specifications are only rough approximations.


All given details and specifications are mean reference values and are not guaranteed. Also, please consider the "Notes on technical specifications".

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Last update 28.02.2022