1、Designation: D542 00 (Reapproved 2006)D542 13Standard Test Method forIndex of Refraction of Transparent Organic Plastics1This standard is issued under the fixed designation D542; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers a pr
3、ocedure for measuring the index of refraction of transparent organic plastic materials.1.2 A refractometer method is presented. This procedure will satisfactorily cover the range of refractive indices found for suchmaterials. Refractive index measurements require optically homogeneous specimens of u
4、niform refractive index.NOTE 1This test method and ISO 489-1983489 are technically equivalent.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health pra
5、ctices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C162 Terminology of Glass and Glass ProductsD618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1898 Practice for Sampling of Plastics (Withdra
6、wn 1998)3E284 Terminology of AppearanceE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standard:ISO 489-1983489 Determination of the Refractive Index of Transparent PlasticsPart A43. Terminology3.1 Definitions:3.1.1 For definitions of terms us
7、ed in this test method, see Terminologies D883 and E284.3.1.2 dispersionvariation of refractive index with wave length of light. C162, C143.1.3 index of refraction, nthe numerical expression of the ratio of the velocity of light in a vacuum to the velocity of lightin a substance at a specified wavel
8、ength. E284, E124. Significance and Use4.1 This test method measures a fundamental property of matter which is useful for the control of purity and composition forsimple identification purposes, and for optical parts design. This test method is capable of readability to four figures to the rightof t
9、he decimal point.5. Apparatus5.1 The apparatus for this test method shall consist of an Abbe refractometer (Note 2), a suitable source of white light, and asmall quantity of a suitable contacting liquid (Note 2 and Note 3).1 This test method is under the jurisdiction of ASTM Committee D20 on Plastic
10、s and is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved Sept. 1, 2006Sept. 1, 2013. Published September 2006September 2013. Originally approved in 1939. Last previous edition approved in 20002006as D542 - 00.D542 - 00 (2006). DOI: 10.1520/D0542-00R06.
11、10.1520/D0542-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historic
12、al standard is referenced on www.astm.org.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.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 th
13、e previous version. Becauseit 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 versionof the standard as published by ASTM is to be considered the official document.*A Summary
14、of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1NOTE 2Other suitable refractometers can be used with appropriate modification to this procedure as described in Section 7.NOTE 3A sa
15、tisfactory contacting liquid is one which will not soften or otherwise attack the surface of the plastic within a period of 2 h of contact.The index of refraction of the liquid must be higher, but not less than one unit in the second decimal place, than the index of the plastic being measured;for ex
16、ample, nd of the sample = 1.500, nd of the contacting liquid 1.510.6. Sampling6.1 Samples shall be in accordance with the pertinent considerations outlined in Practice D1898.6.2 Samples maycan be drawn from any materials presentation (for example, pellets, film, sheet, fabricated articles, etc.) whi
17、chpermits preparation of a satisfactory specimen as described herein.7. Test Specimens7.1 The test specimen shall be of a size that will conveniently fit on the face of the fixed half of the refractometer prisms (Note4). A specimen measuring 6.3 by 12.7 mm on one face is usually satisfactory.NOTE 4F
18、or maximum accuracy in the refractometer method, the surface contacting the prism must be flat. This surface can be is judged for flatness,provided the specimen has been satisfactorily polished, by observing the sharpness of the dividing line between the light and dark field as viewed in theocular.
19、A sharply defined straight dividing line indicates satisfactory contact between the specimen and prism surfaces.7.2 The surface to be used in contact with the prism shall be flat and shall have a good polish. A second edge surfaceperpendicular to the first and on one end of the specimen shall be pre
20、pared with a fair polish (Note 5). The polished surfaces shallintersect without a beveled or rounded edge.NOTE 5It has been found possible to prepare a satisfactorily polished surface by hand polishing small specimens on an abrasive material backed bya piece of plate glass. Fine emery paper (for exa
21、mple, No. 000 Behr-Manning polishing paper) followed by a polishing rouge compound suspended inwater on a piece of parchment paper has successfully been used as the abrasive to produce a polished surface.7.3 A minimum of three specimens should be are prepared and measured.8. Conditioning8.1 Conditio
22、ningCondition the test specimens at 23 6 2C and 50 6 5 %10 % relative humidity for not less than 40 h priorto the test in accordance with Procedure A of Practice D618. In cases of disagreement, the tolerances should be 61C and62 %65 % relative humidity.8.2 Test ConditionsConduct tests at 23 6 2C and
23、 50 6 5 %10 % relative humidity, unless otherwise directed in a pertinentspecification. In cases of disagreement, the tolerances shall be 61C and 62 %65 % relative humidity. If the index of refractionof the material is found to be highly temperature dependent, then the temperature shall be accuratel
24、y controlled to 23 6 0.2C.9. Procedure9.1 Remove the hinged illuminating prism from the refractometer, if necessary. Place a source of diffuse polychromatic lightso that even illumination is obtained along the plane of the surface of contact between the specimen and the refractometer prism.Place a s
25、mall drop of the suitable contacting liquid on the polished surface of the specimen and then place the specimen in firmcontact with the surface of the prism with the polished side of the specimen toward the specified light source. Determine the indexof refraction in the same manner as specified for
26、liquids. This shall be done by moving the index arm of the refractometer untilthe field seen through the eyepiece is one-half dark.Adjust the compensator (Amici prisms) drum to remove all color from the fieldof the ocular. Adjust the index arm using the vernier until the dividing line between the li
27、ght and dark portions of the field exactlycoincides with the intersection of the cross hairs as seen in the eyepiece. Read the value of the index of refraction for the SodiumD Line (see Note 6). Determine the dispersion by reading the compensator drum and applying this figure, along with the indexof
28、 refraction, to a chart or table supplied with the instrument.NOTE 6Sodium light from a sodium burner or discharge lamp is of use in increasing the precision of this test method as well as making the readingof the refractometer easier.9.2 In the case of nonisotropic materials, for example, injection
29、- and compression-molded materials, the index observed is theaverage value for a thin layer of small area at a point of contact near the center of the refractometer prism. For a complete andaccurate determination of the variation of the index throughout the test specimen, it is necessary to make the
30、 measurement at morethan one point on the surface and within the body of the material. This can be done by preparing a contacting surface bothperpendicular and parallel to the molding pressure or flow. After the test specimen is contacted to the prism it may be translatedcarefully for short distance
31、s along the prism surface in the direction of the light source while the variation of index is followedwith the refractometer. This procedure shall be repeated a sufficient number of times and for a sufficient number of specimens todetermine the range of indices involved.The average value and the ra
32、nge of the index readings obtained from these specimens shallbe reported if the range exceeds the accuracy of the measurement. If the variations in index are systematic with the orientation ofthe test specimen, and if these variations exceed those found between specimens of the same material, the na
33、ture of these variationsshall be reported with the average value.D542 13210. Report10.1 Report the following information:10.1.1 The index of refraction to the nearest significant figure warranted by the accuracy and duplicability of the measurement.If the index is specified to more than three signif
34、icant figures, the wavelength of light for which the measurement was made shallbe specified.NOTE 7In the case of nonisotropic materials, for example, injection- and compression-molded materials, the index observed will be the average valuefor a thin layer of small area at a point of contact near the
35、 center of the refractometer prism. For a complete and accurate determination of the variationof the index throughout the test specimen, it is necessary to make the measurement at more than one point on the surface and within the body of thematerial. This can be done by preparing a contacting surfac
36、e both perpendicular and parallel to the molding pressure or flow. After the test specimen iscontacted to the prism it may be translated carefully for short distances along the prism surface in the direction of the light source while the variationof index is followed with the refractometer. This pro
37、cedure should be repeated a sufficient number of times and for a sufficient number of specimens todetermine the range of indices involved. The average value and the range of the index readings obtained from these specimens shall be reported if therange exceeds the accuracy of the measurement. If the
38、 variations in index are systematic with the orientation of the test specimen, and if these variationsexceed those found between specimens of the same material, the nature of these variations shall be reported with the average value.NOTE 7Care should be taken to work rapidly to avoid changes in the
39、refractive index of the plastic due to its absorption of the contacting liquid.10.1.2 The temperature in degrees Celsius at which the index was measured.10.1.3 If available, the dispersion shall be reported along with the index of refraction.11. Precision and Bias511.1 PrecisionA limited round robin
40、 was conducted in 1978, involving seven materials (four polymers and three glassstandards) tested by four laboratories.An individual determination is a test result. Each laboratory obtained six test results for eachmaterial (three determinations on two different days). Statistical tests indicated th
41、ere is no significant difference in the averagesor variances from Day 1 to Day 2 so that both days data were combined. The data in Table 1 and Table 2 are based on this roundrobin.11.1.1 Because of the limited number of laboratories participating in this round robin, interpretation of SR and IR is n
42、otrecommended.11.1.2 Anyone wishing to participate in the development of precision and bias data for this test method should contact theChairman, Subcommittee D20.40, through ASTM Headquarters.NOTE 8The following explanations of Ir and IR (11.3-11.3.3) are only intended to present a meaningful way o
43、f considering the approximate precisionof this test method. The data in Table 1 and Table 2 should not be rigorously applied to acceptance or rejection of material, as those data are specificto the round robin and may not be representative of other lots, conditions, materials, or laboratories.11.2 U
44、sers of this test method shouldshall apply the principles outlined in Practice E691 to generate data specific to theirlaboratory and materials, or between specific laboratories. The principles of 11.3-11.3.3 would then be valid for such data.11.3 Concept of Ir and I RIf S r and SR have been calculat
45、ed from a large enough body of data, and for test results that werefrom testing one specimen:11.3.1 Ir: RepeatabilityComparing two test results for the same material, obtained by the same operator using the sameequipment on the same day, the two test results shouldshall be judged not equivalent if t
46、hey differ by more than the Ir value forthat material.11.3.2 IR: ReproducibilityComparing two test results for the same material, obtained by different operators using differentequipment on different days, the two test results should be judged not equivalent if they differ by more than the IR value
47、for thatmaterial.11.3.3 Any judgment in accordance with 11.3.1 and 11.3.2 would have an approximate 95 % (0.95) probability of being correct.11.4 BiasBias is the systematic error which contributes to the difference between a test result and a true (or reference) value.5 Supporting data are available
48、 from ASTM Headquarters. Request Research Report RR: D20 1154.TABLE 1 PrecisionMaterial Average SrA SRB IrC IRDGlass Standard No. 1 1.356 0.001 0.002 0.003 0.006PTFE 1.366 0.001 0.002 0.003 0.006PVCA 1.477 0.002 0.002 0.006 0.006Glass Standard No. 2 1.490 0.002 0.003 0.006 0.008PA66 0.537 0.002 0.00
49、3 0.006 0.008Glass Standard No. 3 1.567 0.001 0.002 0.002 0.006PF 1.614 0.004 0.004 0.011 0.011A Sr = within-laboratory standard deviation.B SR = between-laboratories standard deviation.C Ir = 2.83 S r.D IR = 2.83 SR.D542 13311.4.1 The data for bias was determined from the three certified glass standards and is reported in Table 2.12. Keywords12.1 dispersion; index of refractionAPPENDIX(Nonmandatory Information)X1. REFRACTIVE INDEX ROUND ROBIN,SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the las
