ASTM C1279-09

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Designation:C1279–05 Designation:C1279–09
Standard Test Method for
Non-Destructive Photoelastic Measurement of Edge and
Surface Stresses in Annealed, Heat-Strengthened, and Fully
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Tempered Flat Glass
This standard is issued under the fixed designation C1279; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of edge stresses and surface stresses in annealed, heat-strengthened, and fully
tempered flat glass products.
1.2 This test method is non-destructive.
1.3 This test method uses transmitted light and is, therefore, applicable to light-transmitting glasses.
1.4 The test method is not applicable to chemically-tempered glass.
1.5 Using the procedure described, surface stresses can be measured only on the “tin” side of float glass.
1.6 Surface-stress measuring instruments are designed for a specific range of surface index of refraction.
1.7
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
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2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
C770 Test Method for Measurement of Glass StressOptical Coefficient
C1048 Specification for Heat-Treated Flat GlassKind HS, Kind FT Coated and Uncoated Glass
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F218Test Method for Measuring Optical Retardation and Analyzing Stress in Glass Practice for Conducting an Interlaboratory
Study to Determine the Precision of a Test Method
2.2 Other Documents:
3
Engineering Standards Manual
4
“Surface and Edge Stress in Tempered Glass”
3. Terminology
3.1 Definitions:
3.1.1 analyzer—a polarizing element, typically positioned between the specimen being evaluated and the viewer.
3.1.2 polarizer—an optical assembly that transmits light vibrating in a single planar direction, typically positioned between a
light source and the specimen being evaluated.
3.1.3 retardation compensator—an optical device, variants of which are used to quantify the optical retardation produced in
transparent birefringent materials: typically positioned between the specimen being evaluated and the analyzer.
3.2 For definition of terms used in this test method, refer to Terminology C162.
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This test method is under the jurisdiction ofASTM Committee C14 on Glass and Glass Products and is the direct responsibility of Subcommittee C14.08 on Flat Glass.
Current edition approved April 1, 2005. Published April 2005.
´1
Originally approved in 1994. Last previous edition approved in 2000 as C1279-00 . DOI: 10.1520/C1279-05.
Current edition approved Oct. 1, 2009. Published October 2009. Originally approved in 1994. Last previous edition approved in 2005 as C1279-05. DOI:
10.1520/C1279-09.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from Glass Association of North America (GANA), 2925 SW Wanamaker Drive, Ste A, Topeka, Kansas 66614–5321. http://www.glasswebsite.com
4
Redner, A. S. and Voloshin, A. S., Proceedings of the Ninth International Conference on Experimental Mechanics, Denmark, 1990.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C1279–09
4. Summary of Test Methods
4.1 Two test methods are described in this standard:
4.1.1 Procedure A—describes a test method for measuring surface stress using light propagating nearly parallel to the surface.
4.1.2 Procedure B—describes a test method for measuring edge-stress using light propagating in the direction perpendicular to
the surface.
4.2 In both methods, the fundamental photoelastic concept is used. As a result of stresses, the material becomes optically
anisotropicorbirefringent.Whenpolarizedlightpropagatesthroughsu
...