ASTM G178-16(2023)
(Practice)Standard Practice for Determining the Activation Spectrum of a Material (Wavelength Sensitivity to an Exposure Source) Using the Sharp Cut-On Filter or Spectrographic Technique
Standard Practice for Determining the Activation Spectrum of a Material (Wavelength Sensitivity to an Exposure Source) Using the Sharp Cut-On Filter or Spectrographic Technique
SIGNIFICANCE AND USE
4.1 The activation spectrum identifies the spectral region(s) of the specific exposure source used that may be primarily responsible for changes in appearance and/or physical properties of the material.
4.2 The spectrographic technique uses a prism or grating spectrograph to determine the effect on the material of isolated narrow spectral bands of the light source, each in the absence of other wavelengths.
4.3 The sharp cut-on filter technique uses a specially designed set of sharp cut-on UV/visible transmitting glass filters to determine the relative actinic effects of individual spectral bands of the light source during simultaneous exposure to wavelengths longer than the spectral band of interest.
4.4 Both the spectrographic and filter techniques provide activation spectra, but they differ in several respects:
4.4.1 The spectrographic technique generally provides better resolution since it determines the effects of narrower spectral portions of the light source than the filter technique.
4.4.2 The filter technique is more representative of the polychromatic radiation to which samples are normally exposed with different, and sometimes antagonistic, photochemical processes often occurring simultaneously. However, since the filters only transmit wavelengths longer than the cut-on wavelength of each filter, antagonistic processes by wavelengths shorter than the cut-on are eliminated.
4.4.3 In the filter technique, separate specimens are used to determine the effect of the spectral bands and the specimens are sufficiently large for measurement of both mechanical and optical changes. In the spectrographic technique, except in the case of spectrographs as large as the Okazaki type (1),4 a single small specimen is used to determine the relative effects of all the spectral bands. Thus, property changes are limited to those that can be measured on very small sections of the specimen.
4.5 The information provided by activation spectra on the spectral r...
SCOPE
1.1 This practice describes the determination of the relative actinic effects of individual spectral bands of an exposure source on a material. The activation spectrum is specific to the light source to which the material is exposed to obtain the activation spectrum. A light source with a different spectral power distribution will produce a different activation spectrum.
1.2 This practice describes two procedures for determining an activation spectrum. One uses sharp cut-on UV/visible transmitting filters and the other uses a spectrograph to determine the relative degradation caused by individual spectral regions.
Note 1: Other techniques can be used to isolate the effects of individual spectral bands of a light source, for example, interference filters.
1.3 The techniques are applicable to determination of the spectral effects of solar radiation and laboratory accelerated test devices on a material. They are described for the UV region, but can be extended into the visible region using different cut-on filters and appropriate spectrographs.
1.4 The techniques are applicable to a variety of materials, both transparent and opaque, including plastics, paints, inks, textiles and others.
1.5 The optical and/or physical property changes in a material can be determined by various appropriate methods. The methods of evaluation are beyond the scope of this practice.
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.
Note 2: There is no ISO standard that is equivalent to this standard.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Develop...
General Information
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: G178 − 16 (Reapproved 2023)
Standard Practice for
Determining the Activation Spectrum of a Material
(Wavelength Sensitivity to an Exposure Source) Using the
1
Sharp Cut-On Filter or Spectrographic Technique
This standard is issued under the fixed designation G178; 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 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This practice describes the determination of the relative
ization established in the Decision on Principles for the
actinic effects of individual spectral bands of an exposure
Development of International Standards, Guides and Recom-
source on a material. The activation spectrum is specific to the
mendations issued by the World Trade Organization Technical
light source to which the material is exposed to obtain the
Barriers to Trade (TBT) Committee.
activation spectrum. A light source with a different spectral
power distribution will produce a different activation spectrum.
2. Referenced Documents
1.2 This practice describes two procedures for determining
2
2.1 ASTM Standards:
an activation spectrum. One uses sharp cut-on UV/visible
D256 Test Methods for Determining the Izod Pendulum
transmitting filters and the other uses a spectrograph to
Impact Resistance of Plastics
determine the relative degradation caused by individual spec-
D638 Test Method for Tensile Properties of Plastics
tral regions.
D822 Practice for Filtered Open-Flame Carbon-Arc Expo-
NOTE 1—Other techniques can be used to isolate the effects of
sures of Paint and Related Coatings
individual spectral bands of a light source, for example, interference
filters.
D1435 Practice for Outdoor Weathering of Plastics
D1499 Practice for Filtered Open-Flame Carbon-Arc Expo-
1.3 The techniques are applicable to determination of the
sures of Plastics
spectral effects of solar radiation and laboratory accelerated
D2244 Practice for Calculation of Color Tolerances and
test devices on a material. They are described for the UV
Color Differences from Instrumentally Measured Color
region, but can be extended into the visible region using
Coordinates
different cut-on filters and appropriate spectrographs.
D2565 Practice for Xenon-Arc Exposure of Plastics In-
1.4 The techniques are applicable to a variety of materials,
tended for Outdoor Applications
both transparent and opaque, including plastics, paints, inks,
D4141 Practice for Conducting Black Box and Solar Con-
textiles and others.
centrating Exposures of Coatings
1.5 The optical and/or physical property changes in a
D4329 Practice for Fluorescent Ultraviolet (UV) Lamp Ap-
material can be determined by various appropriate methods.
paratus Exposure of Plastics
The methods of evaluation are beyond the scope of this
D4364 Practice for Performing Outdoor Accelerated Weath-
practice.
ering Tests of Plastics Using Concentrated Sunlight
D4459 Practice for Xenon-Arc Exposure of Plastics In-
1.6 This standard does not purport to address all of the
tended for Indoor Applications
safety concerns, if any, associated with its use. It is the
D4508 Test Method for Chip Impact Strength of Plastics
responsibility of the user of this standard to establish appro-
3
(Withdrawn 2016)
priate safety, health, and environmental practices and deter-
D4587 Practice for Fluorescent UV-Condensation Expo-
mine the applicability of regulatory limitations prior to use.
sures of Paint and Related Coatings
NOTE 2—There is no ISO standard that is equivalent to this standard.
1 2
This practice is under the jurisdiction of ASTM Committee G03 on Weathering For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Durability and is the direct responsibility of Subcommittee G03.01 on Joint contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Weathering Projects. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Feb. 1, 2023. Published February 2023. Originally the ASTM website.
3
approved in 2003. Last previous edition approved in 2016 as G178 – 16. DOI: The last approved version of this historical standard is referenced on www.ast-
10.1520/G0178-16R23. m.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
G178 − 16 (2023
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.