Glass Thermal Expansion

ULC stocks and has immediate access to a very wide variety of Low Expansion Glass. For more information on any of the following types, click the appropriate link below.


Zerodur is a registered trademark of Schott Glass Technologies. It is a glass ceramic with an extremely low thermal expansion coefficient (~0.02 x 10-6/K at 0-50°C). Zerodur is a glass-ceramic composite material and has both an amorphous (vitreous) component and a crystalline component.


  • Nearly zero thermal expansion with outstanding 3D homogeneity
  • High internal quality
  • Good processing behavior
  • Can be polished to a very high accuracy
  • Can be coated easily
  • Low Helium permeability
  • Non-porous
  • Good chemical stability


  • Optics: Telescopes, optical cavities etc
  • Microlithography: Zerodur is used as a movable mechanical part in wafer stepper and scanner machines to achieve precise and reproducible wafer positioning. Zerodur is an ideal substrate material for reflective optics in the forthcoming EUV lithography due to its almost zero thermal expansion, outstanding homogeneity and good processing behavior.
  • Measurement Technology: The extremely low thermal expansion and proven long-term dimensional stability of Zerodur make it an ideal reference standard for measurement instruments.

Zerodur Constants

  • Dispersion: (nf – nc) = 0.00967
  • Density: 2.53 g/cm3 at 25°C
  • Young’s Modulus: 9.1 x 109 dynes/mm2
  • Poisson Ratio: 0.24
  • Specific Heat at 25°C: 0.196 cal/g°C
  • Coefficient of thermal expansion (20° to 300°C): 0.05 ± 0.10 x 10-6/°C
  • Maximum Temperature: 600°C


The zero expansion titania-silica binary glass ULETM offers an optimum combination of thermal, mechanical, and optical properties which make it an ideal material for precision optical structures and lightweight telescope mirrors. Its near-zero thermal expansion over the ambient operating temperature range helps preserve optical figure; the absence of hysteresis in its thermal expansion curve ensures dimensional stability of the mirror in extreme environments; its low density affords high specific stiffness thereby reducing elastic deformation of lightweight structures; its high fatigue resistance permits higher long-term stress without compromising mechanical reliability; and its excellent optical and birefringence properties facilitate inspection and quality assurance in terms of thermal expansion homogeneity, defect level, and residual strain.


SCHOTT SUPREMAX® 33 is a rolled borosilicate glass utilizing the unique SCHOTT rolled sheet glass process. This manufacturing technique offers a wide range of glass thicknesses with appealing surface quality. The glass composition is identical to SCHOTT BOROFLOAT® 33.

  • Low thermal expansion technical flat glass (C.T.E.: 3.25 x 10-6 K-1)
  • High thermal resistance (long term up to 450° C, short term up to 500° C)
  • Excellent light transmission from UV to NIR
  • Low density (12 % lighter than soda lime glass)
  • Excellent chemical durability
  • Available in wide thickness range (28.6 mm – 66.7 mm


BOROFLOAT® 33 borosilicate glass is SCHOTT’s globally recognized name for high-quality, multi-functional float glass.
This unique specialty float glass is manufactured by SCHOTT Technical Glass Solutions using the Microfloat process and the latest technology.

Its wide range of outstanding product properties, such as its high thermal and chemical resistance, its excellent transparency and its good surface quality, allow access to new and high tech special glass applications.

BOROFLOAT® has proven itself in many traditional applications and, today, there is an increasing area of usage in new and technically sophisticated special glass applications such as electrophoresis, microfluidics and photovoltaics.


United Lens Company stocks PDFClearceram ® produced by Ohara (PDF – 1.54MB)