ASTM C1426-14(2020)

Standard Practices for Verification and Calibration of Polarimeters

ABSTRACT
This practice covers the standards for the verification and calibration of polarimeters required to maintain these instruments and ensure that the optical setup is within specification for satisfactory measurements. Verification and calibration procedures are performed using two types of procedures: Procedure A (verification) and Procedure B (calibration). Procedure A is done by measuring individual components and their orientation to ensure that they comply accordingly. Procedure B is done by determining the accuracy of the polarimeter using a calibrated gage or retarder.
SCOPE
1.1 Polarimeters and polariscopes used for measuring stress in glass are described in Test Methods F218, C148, and C978. These instruments include a light source and several optical elements (polarizers, optical retarders, filters, and so forth) that require occasional cleaning, realigning, and calibration. The objective of these practices is to describe the calibration and verification procedures required to maintain these instruments in calibration and ensure that the optical setup is within specification for satisfactory measurements.  
1.2 It is mandatory throughout these practices that both verification and calibration are carried out by qualified personnel who fully understand the concepts used in measurements of stress retardation and are experienced in the practices of measuring procedures described in Test Methods F218, C148, and C978.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2020
• ICS: 71.040.10 - Chemical laboratories. Laboratory equipment
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

• Replaces: ASTM C1426-14 - Standard Practices for Verification and Calibration of Polarimeters
• Effective Date: 01-Aug-2020
• Refers: ASTM C162-23 - Standard Terminology of Glass and Glass Products
• Effective Date: 01-Oct-2023
• Refers: ASTM C978-04(2019) - Standard Test Method for Photoelastic Determination of Residual Stress in a Transparent Glass Matrix Using a Polarizing Microscope and Optical Retardation Compensation Procedures
• Effective Date: 01-Feb-2019
• Refers: ASTM C770-16 - Standard Test Method for Measurement of Glass Stress—Optical Coefficient
• Effective Date: 01-May-2016
• Refers: ASTM C162-05(2015) - Standard Terminology of<brk type="line"/> Glass and Glass Products
• Effective Date: 01-Nov-2015
• Refers: ASTM C148-14 - Standard Test Methods for Polariscopic Examination of Glass Containers
• Effective Date: 01-May-2014
• Refers: ASTM C978-04(2014) - Standard Test Method for Photoelastic Determination of Residual Stress in a Transparent Glass Matrix Using a Polarizing Microscope and Optical Retardation Compensation Procedures
• Effective Date: 01-May-2014
• Refers: ASTM C770-98(2013) - Standard Test Method for<brk type="line"/> Measurement of Glass Stress&mdash;Optical Coefficient
• Effective Date: 01-Oct-2013
• Refers: ASTM C148-12 - Standard Test Methods for Polariscopic Examination of Glass Containers
• Effective Date: 01-Apr-2012
• Refers: ASTM F218-12 - Standard Test Method for Measuring Optical Retardation and Analyzing Stress in Glass
• Effective Date: 01-Mar-2012
• Refers: ASTM C148-00(2011) - Standard Test Methods for Polariscopic Examination of Glass Containers
• Effective Date: 01-Apr-2011
• Refers: ASTM C978-04(2009) - Standard Test Method for Photoelastic Determination of Residual Stress in a Transparent Glass Matrix Using a Polarizing Microscope and Optical Retardation Compensation Procedures
• Effective Date: 01-May-2009
• Refers: ASTM C770-98(2008) - Standard Test Method for Measurement of Glass Stress&#8212;Optical Coefficient
• Effective Date: 01-Apr-2008
• Refers: ASTM C148-00(2006) - Standard Test Methods for Polariscopic Examination of Glass Containers
• Effective Date: 01-Apr-2006
• Refers: ASTM C162-05(2010) - Standard Terminology of Glass and Glass Products
• Effective Date: 01-Oct-2005

Overview

ASTM C1426-14(2020) - Standard Practices for Verification and Calibration of Polarimeters provides essential guidelines for maintaining the accuracy and performance of polarimeters. These instruments are widely used to measure stress in glass and other transparent materials by analyzing optical properties such as birefringence. The standard outlines systematic procedures for both verification and calibration, ensuring reliable and consistent measurement results in laboratory and industrial settings.

Developed by ASTM International, this standard is designed to meet globally recognized principles as recommended by the World Trade Organization Technical Barriers to Trade (TBT) Committee. The document applies to polarimeters and polariscopes, particularly those used in accordance with ASTM Test Methods F218, C148, and C978 for glass stress measurements.

Key Topics

• Verification and Calibration Procedures:
  The standard details two distinct procedures:

  • Procedure A (Verification): Involves measuring individual polarimeter components and their orientations, including polarizers, optical retarders, and filters, to confirm compliance with relevant test methods.
  • Procedure B (Calibration): Focuses on determining the overall accuracy of the polarimeter using a calibrated gauge or retarder.

• Qualification of Personnel:
  Only qualified personnel familiar with stress measurement concepts and specific ASTM test methods should perform these verification and calibration tasks.

• Instrumentation and Set-Up:
  Key optical elements include:

  • Light source
  • Polarizers (with orientation checks)
  • Optical retarders (including quarter-wave plates)
  • Light-intensity meters
  • Reference gauges with known retardation

• Reporting Requirements:
  Verification and calibration results must be carefully documented, including component details, measurement data, and test conditions.

Applications

The ASTM C1426-14(2020) standard is vital in industries where the measurement of stress in glass and transparent materials is critical to product quality and safety, such as:

• Glass manufacturing and quality control: Ensures polarimetric measurements meet tolerance requirements for residual stress, preventing product failure.
• Research laboratories: Supports accurate analysis of photoelastic properties in transparent specimens.
• Calibration laboratories: Provides a benchmark for verifying the measurement traceability of polarimetric devices.
• Industrial inspection: Key in the optical evaluation of containers, architectural glass, automotive, and specialty glass products.

Proper application of this standard helps organizations maintain compliance with international measurement and quality assurance protocols, minimizing the risk of measurement errors leading to material defects or failures.

Related Standards

ASTM C1426-14(2020) is closely aligned with several other important ASTM standards frequently used together in stress analysis by polarimetry:

• ASTM F218: Test Method for Measuring Optical Retardation and Analyzing Stress in Glass
• ASTM C148: Test Methods for Polariscopic Examination of Glass Containers
• ASTM C978: Method for Photoelastic Determination of Residual Stress in Transparent Glass Using a Polarizing Microscope
• ASTM C770: Test Method for Measurement of Glass Stress-Optical Coefficient
• ASTM C162: Terminology of Glass and Glass Products

Using ASTM C1426 in conjunction with these references ensures a comprehensive approach to the verification and calibration of polarimeters, supporting accurate and reliable stress measurement in glass industry applications.

Keywords

ASTM polarimeter calibration, verification of polarimeters, stress measurement in glass, optical retardation, polariscopic examination, glass quality standards, birefringence analysis, ASTM C1426, calibration procedures, instrument verification.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1426 −14 (Reapproved 2020)
Standard Practices for
Verification and Calibration of Polarimeters
This standard is issued under the fixed designation C1426; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C978Test Method for Photoelastic Determination of Re-
sidual Stress in a Transparent Glass Matrix Using a
1.1 Polarimeters and polariscopes used for measuring stress
Polarizing Microscope and Optical Retardation Compen-
in glass are described in Test Methods F218, C148, and C978.
sation Procedures
These instruments include a light source and several optical
F218Test Method for Measuring Optical Retardation and
elements(polarizers,opticalretarders,filters,andsoforth)that
Analyzing Stress in Glass
require occasional cleaning, realigning, and calibration. The
objective of these practices is to describe the calibration and
3. Terminology
verification procedures required to maintain these instruments
in calibration and ensure that the optical setup is within
3.1 For definitions of terms used in these practices, see
specification for satisfactory measurements.
Terminology C162.
1.2 It is mandatory throughout these practices that both
4. Principles of Verification and Calibration Procedures
verification and calibration are carried out by qualified person-
nelwhofullyunderstandtheconceptsusedinmeasurementsof
4.1 Verification and calibration of polarimeters are accom-
stress retardation and are experienced in the practices of
plished using the following procedures:
measuring procedures described in Test Methods F218, C148,
4.1.1 Procedure A (Verification)—Measure individual com-
and C978.
ponents and their orientation to ensure that the requirements of
1.3 The values stated in SI units are to be regarded as Test Methods F218, C148, and C978 are satisfied.
standard. No other units of measurement are included in this
4.1.2 Procedure B (Calibration)—Determine the accuracy
standard.
of the polarimeter using a calibrated gauge or retarder.
1.4 This international standard was developed in accor-
5. Auxiliary Component Requirements
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5.1 The following are required to verify and calibrate a
Development of International Standards, Guides and Recom-
polarimeter:
mendations issued by the World Trade Organization Technical
5.1.1 Verification of Components (Procedure A):
Barriers to Trade (TBT) Committee.
5.1.1.1 Verification of Polarization Effıciency, a light-
intensity meter, linear over the range of measured values.
2. Referenced Documents
5.1.1.2 Verification of Quarter-wave Plate, a Babinet com-
2.1 ASTM Standards:
pensator equipped polarimeter, with a monochromatic light
C148Test Methods for Polariscopic Examination of Glass
source of traceable wavelength.
Containers
5.1.1.3 Reference Polarizer With Known Axis.
C162Terminology of Glass and Glass Products
5.1.2 Calibration of Polarimeter (Procedure B):
C770Test Method for Measurement of Glass Stress—
5.1.2.1 Procedure B requires a gauge with a calibrated,
Optical Coefficient
known retardation. The calibrated gauge must have sufficient
retardation to calibrate the instrument within its intended use
These practices are under the jurisdiction of ASTM Committee C14 on Glass range. For example, a polariscope/polarimeter used in Test
and Glass Products and are the direct responsibility of Subcommittee C14.04 on
Methods C148 should be calibrated using a gauge exhibiting a
Physical and Mechanical Properties.
retardation range of from 0 to 227 nm (0 to 10 temper grade).
Current edition approved Aug. 1, 2020. Published September 2020. Originally
5.1.2.2 Alternately, a rectangular cross-section specimen
approved in 1999. Last previous addition approved in 2014 as C1426 – 14. DOI:
10.1520/C1426-14R20.
prepared from an SRM glass having a known stress-optical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
constant, subjected to uniaxial compression in a calibrated
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
testing machine, may be used instead of a calibrated gauge
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. with known retardation.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1426 − 14 (2020)
6. Verification and Calibration Procedures 90° in the field of view to bring it into the correct orientation.
Rotate the analyzer clockwise from the zero position until the
6.1 Procedure A—Verification and Aligning of Components:
retarder is uniformly at its darkest hue (maximum extinction)
6.1.1 Verification of Polarization Effıciency—Using a light-
and take the reading from the analyzer dial. Convert the
intensity meter, measure the light intensity, wit
...