Solder Glasses

Product Description

Solder glasses, also referred to as frit glasses, are special glasses with a particularly low softening point (below 550°C). They are used to join glass to other glasses, ceramics, or metals without thermally damaging the materials to be joined. To ensure stress-free sealing, the coefficient of thermal expansion (CTE) needs to be closely matched to the sealing partners.

Types of Glasses

As a solder glass manufacturer, SCHOTT offers different types of glasses to meet customer needs. Three kinds of solder glasses can be distinguished according to their behavior during the soldering process: vitreous solder glasses, devitrifying solder glasses, and composite solder glasses.

Vitreous solder glasses preserve their material properties during soldering and remain in the so-called “glassy” state. When reheated, they show the same softening behavior as prior to the sealing process.

Devitrifying solder glasses crystallize at least partially during the sealing process. Since this results in an increase of softening temperature, they are especially used in applications with high operating temperatures. The crystallization may lead to a change of CTE.

Composite solder glasses were developed to achieve a very low CTE while assuring low soldering temperatures at the same time. This is done by adding inert (non-reactive) fillers with low or negative coefficients of thermal expansion.


  • Full range of glass types for different material combinations and temperatures profiles
  • Lead-free solutions for all major applications
  • Custom formulation of glass type and grain size upon request
  • Full support from sample quantities to mass production


Solder glasses can be used for low temperature joints of different materials in various fields, for example:

Technical Details


Glass powders are manufactured in two steps:
Features / Specifications

The choice of solder glass for joining different materials is dependent on four major aspects:
  • Desired soldering temperature
  • Thermal expansion of the materials to be joined
  • Operation temperature of the final application
  • Chemical behavior
Please refer to the following table for details on some standard SCHOTT solder glass types:

All solder glasses are supplied as glass powder and are available in different grain sizes.

Forms of Supply and Product Packaging

Our standard packaging for solder glasses consists of sealed plastic bottles. For alternative packaging solutions please contact us.

SCHOTT solder glasses:
Glass No.
[10-6 x K-1]
Sealing temperature [oC]
Sealing temperature
tholding [min]
G017-002 3.7 545 700 15 3.6 - 37
G017-339 4.7 325 510 15 4.3 11.5 19
G017-712 5.3 375 510 10 - - -
G017-393 6.5 320 425 15 4.8 11.6 15
G017-340 7.0 315 420 15 4.8 13.4 14
G018-228 7.6 311 400 15 5.0 - -
8465 8.2 385 520 60 5.4 14.9 27
G018-229 8.7 310 410 15 5.4 - -
G018-256 9.6 316 420 15 5.8 - -
G017-052 11.7 308 410 15 6.7 - -
G018-250 7.0 380 540 15 5.7 - -
G018-255 9.4 396 520 15 6.7 - -
8470 10.0 440 680 60 2.8 - -
G018-249 10.1 365 500 15 7.1 - -
Other matched CTE available upon customer request
All frit glasses are available as K3 powder. Grain size: d50 = 10 +- αµm, d99 ≤ 63µm

Other grain sizes available upon request


For more information on the different quality assurance programs, please refer to our quality assurance processes.
Exhibitions & Events
Exhibition CIOE - China International Optoelectronic Exposition, Shenzhen, China, 09-01 to 09-03-2021
Exhibition Gastech, Singapore, Singapore, 09-13 to 09-16-2021
Electronic Packaging
SCHOTT North America, Inc.

15 Wells Street
Southbridge, MA 01550
E-Mail to SCHOTT+1 (508) 765-7450
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