ASTM G178-16

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),3 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 and health practices and determine the applicability of regulatory limitations prior to use.
Note 2: There is no ISO standard that is equivalent to this standard.

General Information

• Status: Historical
• Publication Date: 31-Jan-2016
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: G03 - Weathering and Durability
• Drafting Committee: G03.01 - Joint Weathering Projects

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G178 − 16
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 2. Referenced Documents
2
1.1 This practice describes the determination of the relative 2.1 ASTM Standards:
actinic effects of individual spectral bands of an exposure D256 Test Methods for Determining the Izod Pendulum
source on a material. The activation spectrum is specific to the Impact Resistance of Plastics
light source to which the material is exposed to obtain the D638 Test Method for Tensile Properties of Plastics
activation spectrum. A light source with a different spectral D822 Practice for Filtered Open-Flame Carbon-Arc Expo-
power distribution will produce a different activation spectrum. sures of Paint and Related Coatings
D1435 Practice for Outdoor Weathering of Plastics
1.2 This practice describes two procedures for determining
D1499 Practice for Filtered Open-Flame Carbon-Arc Expo-
an activation spectrum. One uses sharp cut-on UV/visible
sures of Plastics
transmitting filters and the other uses a spectrograph to
D2244 Practice for Calculation of Color Tolerances and
determine the relative degradation caused by individual spec-
Color Differences from Instrumentally Measured Color
tral regions.
Coordinates
NOTE 1—Other techniques can be used to isolate the effects of
D2565 Practice for Xenon-Arc Exposure of Plastics In-
individual spectral bands of a light source, for example, interference
filters.
tended for Outdoor Applications
D4141 Practice for Conducting Black Box and Solar Con-
1.3 The techniques are applicable to determination of the
centrating Exposures of Coatings
spectral effects of solar radiation and laboratory accelerated
D4329 Practice for Fluorescent Ultraviolet (UV) Lamp Ap-
test devices on a material. They are described for the UV
paratus Exposure of Plastics
region, but can be extended into the visible region using
D4364 Practice for Performing Outdoor Accelerated Weath-
different cut-on filters and appropriate spectrographs.
ering Tests of Plastics Using Concentrated Sunlight
1.4 The techniques are applicable to a variety of materials,
D4459 Practice for Xenon-Arc Exposure of Plastics In-
both transparent and opaque, including plastics, paints, inks,
tended for Indoor Applications
textiles and others.
D4508 Test Method for Chip Impact Strength of Plastics
1.5 The optical and/or physical property changes in a
D4587 Practice for Fluorescent UV-Condensation Expo-
material can be determined by various appropriate methods.
sures of Paint and Related Coatings
The methods of evaluation are beyond the scope of this
D5031 Practice for Enclosed Carbon-Arc Exposure Tests of
practice.
Paint and Related Coatings
D6360 Practice for Enclosed Carbon-Arc Exposures of Plas-
1.6 This standard does not purport to address all of the
tics
safety concerns, if any, associated with its use. It is the
D6695 Practice for Xenon-Arc Exposures of Paint and
responsibility of the user of this standard to establish appro-
Related Coatings
priate safety and health practices and determine the applica-
E275 Practice for Describing and Measuring Performance of
bility of regulatory limitations prior to use.
Ultraviolet and Visible Spectrophotometers
NOTE 2—There is no ISO standard that is equivalent to this standard.
E313 Practice for Calculating Yellowness and Whiteness
Indices from Instrumentally Measured Color Coordinates
1
This practice is under the jurisdiction of ASTM Committee G03 on Weathering
and Durability and is the direct responsibility of Subcommittee G03.01 on Joint
2
Weathering Projects. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2016. Published February 2016. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2003. Last previous edition approved in 2009 as G178 – 09. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0178-16. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G178 − 16
E925 Practice for Monitoring the Calibration of Ultraviolet- 3.2.5 spectral band, n—the spectral region defined by the
Visible Spectrophotometers whose Spectral Bandwidth difference in transmittance of a
...

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: G178 − 09 G178 − 16
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
1.1 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 and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 2—There is no ISO standard that is equivalent to this standard.
2. Referenced Documents
2
2.1 ASTM Standards:
D256 Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
D638 Test Method for Tensile Properties of Plastics
D822 Practice for Filtered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings
D1435 Practice for Outdoor Weathering of Plastics
D1499 Practice for Filtered Open-Flame Carbon-Arc Exposures of Plastics
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D2565 Practice for Xenon-Arc Exposure of Plastics Intended for Outdoor Applications
D4141 Practice for Conducting Black Box and Solar Concentrating Exposures of Coatings
D4329 Practice for Fluorescent Ultraviolet (UV) Lamp Apparatus Exposure of Plastics
D4364 Practice for Performing Outdoor Accelerated Weathering Tests of Plastics Using Concentrated Sunlight
D4459 Practice for Xenon-Arc Exposure of Plastics Intended for Indoor Applications
D4508 Test Method for Chip Impact Strength of Plastics
D4587 Practice for Fluorescent UV-Condensation Exposures of Paint and Related Coatings
1
This practice is under the jurisdiction of ASTM Committee G03 on Weathering and Durability and is the direct responsibility of Subcommittee G03.01 on Joint
Weathering Projects.
Current edition approved April 15, 2009Feb. 1, 2016. Published June 2009February 2016. Originally approved in 2003. Last previous edition approved in 20032009 as
G178–03. DOI: 10.1520/G0178-09. – 09. DOI: 10.1520/G0178-16.
2
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
1

---------------------- Page: 1 ----------------------
G178 − 16
D5031 Practice for Enclosed Carbon-Arc Exposure Tests of Paint and Related Coatings
D6360 Practice for Enclosed Carbon-Arc Exposures of Plastics
D6695 Practice for Xenon-Arc Exposures of Paint and Related Coatings
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
...