ASTM E1967-19

Standard Test Method for the Automated Determination of Refractive Index of Glass Samples Using the Oil Immersion Method and a Phase Contrast Microscope

SIGNIFICANCE AND USE
4.1 This test method is useful for accurate measurement of  from a wide variety of glass samples, whose  ranges from 1.48–1.55.  
4.2 It should be recognized that measurement of surface fragments, especially from float glass samples, can result in refractive index values which are different than the refractive index values of fragments from the interior of (for example, bulk) the same broken glass source (5).  
4.3 The precision of this test method shall be established in each laboratory that employs it as part of the validation protocol (see Section 9).  
4.4 It should be recognized that this technique measures the refractive index of the glass at the match point temperature, which will be higher than ambient temperature, and thus, may give different  values from those obtained by other methods, which measure the refractive index at room temperature.
SCOPE
1.1 This test method covers a procedure for measuring and comparing the refractive index (η) at a fixed wavelength (λ) and temperature (T) ( ) of glass from known sources to recovered fragments from a questioned source.  
1.2 This test method does not include the measurement of optical dispersion or the measurement of refractive index ( ) at any other wavelength other than the Sodium D line ( ). This method employs a narrow band pass filter at 589 nm, but other filters could be employed using the described method, allowing the  to be determined at other wavelengths, and therefore, also allowing for the dispersion value to be calculated.  
1.3 Alternative methods for the determination of  are listed in Refs (1-5).2  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard cannot replace knowledge, skills, or abilities acquired through education, training, and experience and is to be used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.  
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 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: 30-Sep-2019
• ICS: 81.040.01 - Glass in general
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.01 - Criminalistics

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: E1967 − 19 An American National Standard
Standard Test Method for
the Automated Determination of Refractive Index of Glass
Samples Using the Oil Immersion Method and a Phase
1
Contrast Microscope
This standard is issued under the fixed designation E1967; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers a procedure for measuring and
comparing the refractive index (η) at a fixed wavelength (λ)
2. Referenced Documents
T
and temperature (T)(η ) of glass from known sources to
λ 3
2.1 ASTM Standards:
recovered fragments from a questioned source.
E177Practice for Use of the Terms Precision and Bias in
1.2 This test method does not include the measurement of
ASTM Test Methods
T
optical dispersion or the measurement of refractive index (η )
λ E691Practice for Conducting an Interlaboratory Study to
T
at any other wavelength other than the Sodium D line (η ).
D
Determine the Precision of a Test Method
This method employs a narrow band pass filter at 589 nm, but
3. Summary of Test Method
other filters could be employed using the described method,
T
allowing the η to be determined at other wavelengths, and
3.1 Oil immersion refractometry is used to determine the
λ
therefore, also allowing for the dispersion value to be calcu-
refractive index of glass fragments. The glass fragments are
lated.
mounted on a glass microscope slide in an immersion oil of
T
known refractive index over the temperature range of interest.
1.3 Alternative methods for the determination of η are
λ
2
The glass microscope slide is placed on a phase contrast
listed in Refs (1-5).
microscope mounted with a hot stage and a video camera.The
1.4 The values stated in SI units are to be regarded as
phase contrast microscope is employed with illumination at a
standard. No other units of measurement are included in this
fixed wavelength (nominally Sodium D) to magnify the image
standard.
of glass particles immersed in the silicone oil.The microscope
1.5 This standard cannot replace knowledge, skills, or
is aligned to produce even illumination with maximum con-
abilities acquired through education, training, and experience
trast. A video camera is attached to a photography port (the
and is to be used in conjunction with professional judgment by
output of the image) to observe the immersed glass and
individuals with such discipline-specific knowledge, skills, and
measure the contrast between the glass and the oil. The
abilities.
temperature of the oil is changed via the hot stage and an
electronic temperature controller until the glass particles’
1.6 This standard does not purport to address all of the
image disappears. The temperature of the oil at which there is
safety concerns, if any, associated with its use. It is the
minimum contrast between the glass and the liquid then is
responsibility of the user of this standard to establish appro-
recorded manually or electronically as the match temperature.
priate safety, health, and environmental practices and deter-
T
mine the applicability of regulatory limitations prior to use.
3.2 The match temperature is converted to η by reference
D
1.7 This international standard was developed in accor-
to a calibration curve for the immersion oil. This calibration
dance with internationally recognized principles on standard-
curve has been previously created by measuring the match
ization established in the Decision on Principles for the
temperatures of traceable reference glass standards of known
T
Development of International Standards, Guides and Recom-
η within the temperature range of interest. This curve or its
D
mathematical equivalent normally is stored within the com-
T
puter and used to determine the η of any glass of interest,
D
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE30onForensic
whether it is a fragment of known origin or a recovered
Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.
Current edition approved Oct. 1, 2019. Published October 2019. Originally
3
approved in 1998. Last previous edition approved in 2011 as E1967–11a. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E1967-19. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
2
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof Sta
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1967 − 11a E1967 − 19
Standard Test Method for
the Automated Determination of Refractive Index of Glass
Samples Using the Oil Immersion Method and a Phase
1
Contrast Microscope
This standard is issued under the fixed designation E1967; 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
t
1.1 This test method covers a procedure for measuring and comparing the refractive index (η(η) ) of glass samples, irregularly
λ
T
shaped and as small at a fixed wavelength (λ) and temperature (T as) (η 300 μg, for the comparison of fragments of a known
λ
source) of glass from known sources to recovered fragments from a questioned source.
t
T
1.2 This test method does not include the measurement of optical dispersion or the measurement of refractive index (η( η ) at
λ λ
t
T
any other wavelength other than the Sodium D line (η( η ). This method employs a narrow band pass filter at 589 nm, but other
D
D
t
T
filters could be employed using the described method and method, allowing the ηη to be determined at other wavelengths, and
λλ
therefore, also allowing for the dispersion value to be calculated.
t 2
T
1.3 Alternative methods for the determination of ηη are listed in Refs (1-5).
λλ
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard cannot replace knowledge, skills, or abilities acquired through education, training, and experience and is to
be used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.
1.6 This standard test method 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 safety, health, and healthenvironmental practices and
determine the applicability of regulatory limitations prior to use.
1.7 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.
2. Referenced Documents
3
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Summary of Test Method
3.1 A Oil immersion refractometry is used to determine the refractive index of glass fragments. The glass fragments are
mounted on a glass microscope slide in an immersion oil of known refractive index over the temperature range of interest. The
glass microscope slide is placed on a phase contrast microscope mounted with a hot stage and a video camera. The phase contrast
microscope is employed with illumination at a fixed wavelength (nominally Sodium D) to magnify the image of glass particles
while these are immersed in athe silicone oil. The microscope is aligned to produce even illumination with maximum contrast and
a contrast. A video camera is attached to an eyepiece a photography port (the output of the image) to observe the immersed glass
and measure the contrast ofbetween the image ofglass and the glass.oil. The temperature of the oil is changed via athe hot stage
1
This practice test method is under the jurisdiction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.01 on
Criminalistics.
Current edition approved Dec. 1, 2011Oct. 1, 2019. Published December 2011October 2019. Originally approved in 1998. Last previous edition approved in 2011 as
E1967 – 11.E1967 – 11a. DOI: 10.1520/E1967-11A.10.1520/E1967-19.
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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