Borosilicate Glass Tubing and Rod SCHOTT 8242

Alternative and trade names
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For sealing to kovar metal and molybdenum. Electrically highly insulating.

This material data has been provided by Schott Glass Tubing.

"Typical" values were obtained via a literature search. "Predicted" values were imputed via artificial intelligence technology. While we have placed significant efforts in ensuring data accuracy, "typical" and "predicted" data should be considered indicative and verified by appropriate material testing. Please do contact us if additional information on the the predicted data method is required.
All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.

Ashby charts





2.27 g/cm³

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PropertyValueTesting StandardComment

Annealing temperature

480.0 °C

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ISO 7884-4

Viscosity 10¹³ dPa·s

Coefficient of thermal expansion

4.7e-06 1/K

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ISO 7991

mean value for 20-300 °C

Glass transition temperature

465 °C

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ISO 7884-8

Softening temperature

715.0 °C

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ISO 7884-3

Viscosity 10⁷·⁶ dPa·s

Working temperature

1130.0 °C

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ISO 7884-2

Viscosity 10⁴ dPa·s



Refractive index

1.5 [-]

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at λ=587.6 nm

Chemical properties



0.01 %

max., Lead, Cadmium, Mercury and Hexavalent Chromium

Technological properties

Application areas

For use in clad tube for optical fibers, Endoscopy

Corrosion properties

Hydrolytic resistance Class HGB2 (ISO 719) - Acid resistance Class S4 (DIN 12116) - Alkali resistance Class A3 (ISO695)