ASTM D542-00 pdf free.Standard Test Method for Index of Refraction of Transparent Organic Plastics.
Remove the hinged illuminating prism from 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 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 field 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 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.
Report the following information:The index of refraction to the nearest significantfigure warranted by the accuracy and duplicability of themeasurement. If the index is specified to more than threesignificant figures，the wavelength of light for which themeasurement was made shall be specified.
Because of the limited number of laboratories participating in this round robin, interpretation of S and IR is notrecommended. Anyone wishing to participate in the development ofprecision and bias data for this test method should contact theChairman，Subcommittee D20.40,through ASTM Headquarters.
Users 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.ASTM D542 pdf download.