ASTM F218-95

Standard Test Method for Analyzing Stress in Glass

SCOPE
1.1 This test method covers the analysis of stress in glass by means of a polarimeter based on the principles developed by de Senarmont and Friedel (1,2). Stress is evaluated as a function of optical retardation. Retardation is expressed as the angle of rotation of an analyzing polarizer that causes extinction in the glass.
1.2 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-1999
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

• Replaced By: ASTM F218-95(2000) - Standard Test Method for Analyzing Stress in Glass
• Effective Date: 01-Jan-2000
• Referred By: ASTM F144-80(2019) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Jan-2000
• Referred By: ASTM C770-16(2020) - Standard Test Method for Measurement of Glass Stress—Optical Coefficient
• Effective Date: 01-Jan-2000
• Referred By: ASTM F140-98(2020) - Standard Practice for Making Reference Glass-Metal Butt Seals and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Jan-2000
• Referred By: ASTM E671-98(2022) - Standard Specification for Maximum Permissible Thermal Residual Stress in Annealed Glass Laboratory Apparatus
• Effective Date: 01-Jan-2000
• Referred By: 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-Jan-2000
• Referred By: ASTM C1426-14(2020) - Standard Practices for Verification and Calibration of Polarimeters
• Effective Date: 01-Jan-2000
• Referred By: ASTM C1422/C1422M-20a - Standard Specification for Chemically Strengthened Flat Glass
• Effective Date: 01-Jan-2000
• Referred By: ASTM F14-80(2019) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-Jan-2000

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 218 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Analyzing Stress in Glass
This standard is issued under the fixed designation F 218; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the analysis of stress in glass by
means of a polarimeter based on the principles developed by de
Sénarmont and Friedel (1,2). Stress is evaluated as a function
of optical retardation. Retardation is expressed as the angle of
A—Light source (white, sodium vapor, or mercury vapor arc)
rotation of an analyzing polarizer that causes extinction in the
B—Filter (used only with mercury arc light)
glass.
C—Diffuser
1.2 This standard does not purport to address all of the
D—Polarizer
E—Immersion cell
safety concerns, if any, associated with its use. It is the
F—Full-wave plate (used only with white light)
responsibility of the user of this standard to establish appro-
G—Quarter-wave plate
priate safety and health practices and determine the applica-
H—Analyzer
I—Telescope
bility of regulatory limitations prior to use.
FIG. 1 Polarimeter
2. Polarimeter
2.1 The polarimeter shall consist of an arrangement similar
Liquid Refractive Index
to that shown in Fig. 1. A description of each component
Cinnamic aldehyde 1.62
follows:
Oil of cassia 1.61
2.1.1 Source of Light—Either a white light or a monochro-
Monochlorobenzene 1.525
Carbon tetrachloride 1.463
matic source such as sodium light (l 589 nm) or a mercury-
Dipentene (Eastman) 1.473
vapor arc lamp of the high-pressure type, preferably the latter.
NOTE 3—Cases may arise where the refraction liquid may contaminate
NOTE 1—The white light should provide a source of illumination with
the specimen. If it is viewed through sides that are essentially parallel
solar temperature of at least that of Illuminant A.
elimination of the liquid will cause only a minor error. However, when
viewing through sides that are not parallel, the use of a refraction liquid is
2.1.2 Filter— In order to render the light monochromatic, a
essential.
narrow band-pass filter should be used.
2.1.3 Diffuser—A piece of opal glass or a ground glass of
2.1.6 Full-Wave (Sensitive Tint) Plate, having a retardation
photographic quality.
of 565 nm which produces, with white light, a violet-red color.
2.1.4 Polarizer—A polarizing element housed in a rotatable
It should be housed in a rotatable mount capable of being
mount capable of being locked in a fixed position.
locked in a fixed position.
2.1.5 Immersion Cell—Rectangular glass jar with strain-
2.1.7 Quarter-Wave Plate, having a retardation equivalent
free sides filled with a liquid having the same index of
to one quarter of the wavelength of light being used. It should
refraction as the glass specimen to be measured. It may be
be housed in a rotable mount capable of being locked in a fixed
surmounted with a suitable device for holding and rotating the
position.
specimen, such that it does not stress the specimen.
2.1.8 Analyzer—Identical to the polarizer. It should be
housed in a rotatable mount capable of being locked in a fixed
NOTE 2—Suitable index liquids may be purchased or mixed as required.
position. This mount must then be housed within a graduated
Dibutyl phthalate (refractive index 1.489), and tricresyl phosphate (index
1.555) may be mixed to produce any desired refractive index between the mount capable of being rotated 360°.
two limits, the refractive index being a linear function of the proportion of
2.1.9 Telescope, short-focus, having a suitable magnifying
one liquid to the other. Other liquids that may be used are:
power over the usable focusing range.
3. Setup of Polarimeter
This test method is under the jurisdiction of ASTM Committee C-14 on Glass
3.1 As usually employed, the polarimeter measures retarda-
and Glass Products and is the direct responsibility of Subcommittee C14.04 on
Physical and Mechanical Properties.
tions in a vertical or a horizontal direction. This is accom-
Current edition approved Sept. 10, 1995. Published November 1995. Originally
plished by setting the vibration direction of the polarizer at an
published as B 218 – 50. Last previous edition F 218 – 68 (1989).
angle of 45° to the vertical and horizontal in either a northwest-
The boldface numbers in parentheses refer to the reports and papers appearing
in the list of references at the end of this test method. southeast or a northeast-southwest direction (Fig. 2). The
F 218
NOTE 1—The directions of vibration of the polarizer and analyzer may be oriented 90° from the indicated positions.
FIG. 2 Orientation of Polarimeter in Standard Position
vibration direction of the analyzer must be “crossed” with ground color is seen when the three elements (polarizer,
respect to that of the polarizer; that is, the two directions must full-wave plate, and analyzer) are placed in series.
be at right angles to each other. In this relationship a minimum 3.4 Paragraphs 3.2 and 3.3 describe orientations of the
amount of light will pass through the combination. To check quarter- and full-wave plates in the standard positions that have
the 45° angle at which the directions of the polarizer and been generally adopted. However, the direction of the“ slow”
analyzer must be set, use may be made of a rectangular-shaped rays may be rotated 90° without changing the functions of the
Glan-Thompson or Nicol prism. The prism is set so that its apparatus. This does, however, cause the analyzer rotations (in
vibration direction is 45° to the vertical and horizontal. The the case of the quarter-wave plate) and the colors (in the case
polarizer is then rotated until extinction occurs between it and of the full-wave plate) to have opposite meanings. Table 1 and
the prism. The position of the analyzer is then determined in Table 2 define these meanings in whatever is being measured
the same way, but by first rotating the Glan-Thompson or Nicol or observed with the “slow” ray directions in either the
prism through 90°; or, the analyzer may be rotated to extinction standard or the alternate positions.
with respect to the polarizer after the latter has been set in 3.5 To assure proper orientation of the directions of the
position with the prism. “slow” ray of the quarter-wave and full-wave plates with
3.2 When a quarter-wave plate is used, its “slow” ray respect to the vibration directions of the polarizer and analyzer,
direction must be set in a northwest-southeast direction (Fig. use may be made of a U-shaped piece of annealed cane glass
2). Adjusted in this position, maximum extinction occurs when as illustrated in Fig. 3. Squeezing the legs together slightly will
direction of axes of all three elements (polarizer, analyzer and develop a tensile stress on the outside and a compressive stress
quarter-wave plate) are in agreement with Fig. 2. on the inside. Then, if the“ slow” ray directions of the
3.3 When the full-wave plate is used with the quarter-wave quarter-wave and full-wave plates are oriented in the standard
plate, its “slow” ray direction must be placed in a horizontal positions, the stress conditions of Columns 1 through 4 and 9
position (Fig. 2). Adjusted in this position, a violet-red back- through 12 of Table 1 and Table 2 will be noted in the vertical
TABLE 1 Orientation of“ Slow” Ray Direction of Quarter-Wave Plate with Corresponding Stresses
When
orientation of
“slow” ray with (standard)
...