1、Designation: D 542 00 (Reapproved 2006)Standard Test Method forIndex of Refraction of Transparent Organic Plastics1This standard is issued under the fixed designation D 542; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 proced
3、ure for measuring theindex of refraction of transparent organic plastic materials.1.2 A refractometer method is presented. This procedurewill satisfactorily cover the range of refractive indices foundfor such materials. Refractive index measurements requireoptically homogeneous specimens of uniform
4、refractive index.NOTE 1This test method and ISO 489-1983 are technically equiva-lent.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices an
5、d determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 162 Terminology of Glass and Glass ProductsD 618 Practice for Conditioning Plastics for TestingD 883 Terminology Relating to PlasticsD 1898 Practice for Sampling of Plastics3E 284 Termi
6、nology of AppearanceE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:ISO 489-1983 Determination of the Refractive Index ofTransparent PlasticsPart A43. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,
7、 seeTerminologies D 883 and E 284.3.1.2 dispersionvariation of refractive index with wavelength of light. C 162, C143.1.3 index of refraction, nthe numerical expression of theratio of the velocity of light in a vacuum to the velocity of lightin a substance at a specified wavelength. E 284, E124. Sig
8、nificance and Use4.1 This test method measures a fundamental property ofmatter which is useful for the control of purity and compositionfor simple identification purposes, and for optical parts design.This test method is capable of readability to four figures to theright of the decimal point.5. Appa
9、ratus5.1 The apparatus for this test method shall consist of anAbbe refractometer (Note 2), a suitable source of white light,and a small quantity of a suitable contacting liquid (Note 2 andNote 3).NOTE 2Other suitable refractometers can be used with appropriatemodification to this procedure as descr
10、ibed in Section 7.NOTE 3Asatisfactory contacting liquid is one which will not soften orotherwise attack the surface of the plastic within a period of2hofcontact.The index of refraction of the liquid must be higher, but not less than oneunit in the second decimal place, than the index of the plastic
11、beingmeasured; for example, ndof the sample = 1.500, ndof the contactingliquid $1.510.6. Sampling6.1 Samples shall be in accordance with the pertinentconsiderations outlined in Practice D 1898.6.2 Samples may be drawn from any materials presentation(for example, pellets, film, sheet, fabricated arti
12、cles, etc.)which permits preparation of a satisfactory specimen as de-scribed herein.7. Test Specimens7.1 The test specimen shall be of a size that will conve-niently fit on the face of the fixed half of the refractometerprisms (Note 4).Aspecimen measuring 6.3 by 12.7 mm on oneface is usually satisf
13、actory.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 1939. Last previous edition approved in 2000 as D
14、542 - 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standar
15、ds Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 4For maximum accuracy in the refractometer metho
16、d, thesurface contacting the prism must be flat. This surface can be judged forflatness, provided the specimen has been satisfactorily polished, byobserving the sharpness of the dividing line between the light and darkfield as viewed in the ocular. A sharply defined straight dividing lineindicates s
17、atisfactory contact between the specimen and prism surfaces.7.2 The surface to be used in contact with the prism shall beflat and shall have a good polish. A second edge surfaceperpendicular to the first and on one end of the specimen shallbe prepared with a fair polish (Note 5). The polished surfac
18、esshall intersect without a beveled or rounded edge.NOTE 5It has been found possible to prepare a satisfactorily polishedsurface by hand polishing small specimens on an abrasive material backedby a piece of plate glass. Fine emery paper (for example, No. 000Behr-Manning polishing paper) followed by
19、a polishing rouge compoundsuspended in water on a piece of parchment paper has successfully beenused as the abrasive to produce a polished surface.7.3 A minimum of three specimens should be prepared andmeasured.8. Conditioning8.1 ConditioningCondition the test specimens at 23 62C and 50 6 5 % relati
20、ve humidity for not less than 40 h priorto the test in accordance with Procedure A of Practice D 618.In cases of disagreement, the tolerances should be 61C and62 % relative humidity.8.2 Test ConditionsConduct tests at 23 6 2C and 50 65 % relative humidity, unless otherwise directed in a pertinentspe
21、cification. In cases of disagreement, the tolerances shall be61C and 62 % relative humidity. If the index of refraction ofthe material is found to be highly temperature dependent, thenthe temperature shall be accurately controlled to 23 6 0.2C.9. Procedure9.1 Remove the hinged illuminating prism fro
22、m the refrac-tometer, if necessary. Place a source of diffuse polychromaticlight so that even illumination is obtained along the plane of thesurface of contact between the specimen and the refractometerprism. Place a small drop of the suitable contacting liquid onthe polished surface of the specimen
23、 and then place thespecimen in firm contact with the surface of the prism with thepolished side of the specimen toward the specified light source.Determine the index of refraction in the same manner asspecified for liquids. This shall be done by moving the indexarm of the refractometer until the fie
24、ld seen through theeyepiece is one-half dark. Adjust the compensator (Amiciprisms) drum to remove all color from the field of the ocular.Adjust the index arm using the vernier until the dividing linebetween the light and dark portions of the field exactlycoincides with the intersection of the cross
25、hairs as seen in theeyepiece. Read the value of the index of refraction for theSodium D Line (see Note 6). Determine the dispersion byreading the compensator drum and applying this figure, alongwith the index of refraction, to a chart or table supplied withthe instrument.NOTE 6Sodium light from a so
26、dium burner or discharge lamp is ofuse in increasing the precision of this test method as well as making thereading of the refractometer easier.10. Report10.1 Report the following information:10.1.1 The index of refraction to the nearest significantfigure warranted by the accuracy and duplicability
27、of themeasurement. If the index is specified to more than threesignificant figures, the wavelength of light for which themeasurement was made shall be specified.NOTE 7In the case of nonisotropic materials, for example, injection-and compression-molded materials, the index observed will be the averag
28、evalue for a thin layer of small area at a point of contact near the center ofthe refractometer prism. For a complete and accurate determination of thevariation of the index throughout the test specimen, it is necessary to makethe measurement at more than one point on the surface and within thebody
29、of the material. This can be done by preparing a contacting surfaceboth perpendicular and parallel to the molding pressure or flow. After thetest specimen is contacted to the prism it may be translated carefully forshort distances along the prism surface in the direction of the light sourcewhile the
30、 variation of index is followed with the refractometer. Thisprocedure should be repeated a sufficient number of times and for asufficient number of specimens to determine the range of indices involved.The average value and the range of the index readings obtained from thesespecimens shall be reporte
31、d if the range exceeds the accuracy of themeasurement. If the variations in index are systematic with the orientationof the test specimen, and if these variations exceed those found betweenspecimens of the same material, the nature of these variations shall bereported with the average value.NOTE 8Ca
32、re should be taken to work rapidly to avoid changes in therefractive index of the plastic due to its absorption of the contacting liquid.10.1.2 The temperature in degrees Celsius at which theindex was measured.10.1.3 If available, the dispersion shall be reported alongwith the index of refraction.11
33、. Precision and Bias511.1 PrecisionA limited round robin was conducted in1978, involving seven materials (four polymers and three glassstandards) tested by four laboratories. An individual determi-nation is a test result. Each laboratory obtained six test resultsfor each material (three determinatio
34、ns on two different days).Statistical tests indicated there is no significant difference in theaverages or variances from Day 1 to Day 2 so that both daysdata were combined. The data in Table 1 and Table 2 are basedon this round robin.5Supporting data are available from ASTM Headquarters. Request Re
35、searchReport RR: D20 1154.TABLE 1 PrecisionMaterial Average SrASRBIrCIRDGlass 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 0.003 0.006 0.008Glass Standard No. 3 1.567
36、 0.001 0.002 0.002 0.006PF 1.614 0.004 0.004 0.011 0.011ASr= within-laboratory standard deviation.BSR= between-laboratories standard deviation.CIr= 2.83 Sr.DIR= 2.83 SR.D 542 00 (2006)211.1.1 Because of the limited number of laboratories par-ticipating in this round robin, interpretation of SRand IR
37、is notrecommended.11.1.2 Anyone wishing to participate in the development ofprecision and bias data for this test method should contact theChairman, Subcommittee D20.40, through ASTM Headquar-ters.NOTE 9The following explanations of Irand IR(11.3-11.3.3) are onlyintended to present a meaningful way
38、of considering the approximateprecision of this test method. The data in Table 1 and Table 2 should notbe rigorously applied to acceptance or rejection of material, as those dataare specific to the round robin and may not be representative of other lots,conditions, materials, or laboratories.11.2 Us
39、ers of this test method should apply the principlesoutlined in Practice E 691 to generate data specific to theirlaboratory and materials, or between specific laboratories. Theprinciples of 11.3-11.3.3 would then be valid for such data.11.3 Concept of Irand IRIf Srand SRhave beencalculated from a lar
40、ge enough body of data, and for test resultsthat were from testing one specimen:11.3.1 Ir: RepeatabilityComparing two test results for thesame material, obtained by the same operator using the sameequipment on the same day, the two test results should bejudged not equivalent if they differ by more t
41、han the Irvaluefor that material.11.3.2 IR: ReproducibilityComparing two test results forthe same material, obtained by different operators using differ-ent equipment on different days, the two test results should bejudged not equivalent if they differ by more than the IRvaluefor that material.11.3.
42、3 Any judgment in accordance with 11.3.1 and 11.3.2would have an approximate 95 % (0.95) probability of beingcorrect.11.4 BiasBias is the systematic error which contributes tothe difference between a test result and a true (or reference)value.11.4.1 The data for bias was determined from the threecer
43、tified glass standards and is reported in Table 2.12. Keywords12.1 dispersion; index of refractionAPPENDIX(Nonmandatory Information)X1. REFRACTIVE INDEX ROUND ROBIN,TABLE 2 BiasMaterialCertifiedValueTestAverageBiasStatisticallySignificantAGlass Standard No. 1 1.3554 1.3556 +0.0002 NoGlass Standard N
44、o. 2 1.4903 1.4897 0.0006 NoGlass Standard No. 3 1.5684 1.5673 0.0011 YesA“t”-test (a = 0.05) = bias/Sr/ =n ).D 542 00 (2006)3SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue (D 542 - 00)that may impact the use of this standard. (S
45、eptember 1, 2006)(1) Reapproved without change.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights,
46、and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revi
47、sion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you
48、shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be o
49、btained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE X1.1 Test of Variance Between DaysMaterial Sr(1)ASr(2)AFBSR(1)ASR(2)AFBStandard Glass No. 1 0.011 0.007 2.47 0.0016 0.0017 1.13PTFE 0.0015 0.0016 1.14 0.0017 0.0016 1.13PVAC 0.0023 0.0016 2.07 0.0024 0.0016 2.25Standard Glass No. 2 0.0023 0.0021 1.20 0.0029 0.0026 1.24PA66 0.0021 0.0025 1.42 0.0032 0.0025 1.64Standard Glass No. 3 0.0008 0.0007 1.31 0.0019 0.0021 1.22PF 0.0050 0.0051 1
