ASTM C1648-2012 Standard Guide for Choosing a Method for Determining the Index of Refraction and Dispersion of Glass《选用一种方法测定玻璃折射和色散系数的标准指南》.pdf
《ASTM C1648-2012 Standard Guide for Choosing a Method for Determining the Index of Refraction and Dispersion of Glass《选用一种方法测定玻璃折射和色散系数的标准指南》.pdf》由会员分享,可在线阅读,更多相关《ASTM C1648-2012 Standard Guide for Choosing a Method for Determining the Index of Refraction and Dispersion of Glass《选用一种方法测定玻璃折射和色散系数的标准指南》.pdf(17页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: C1648 06 C1648 12Standard Guide forChoosing a Method for Determining the Index of Refractionand Dispersion of Glass1This standard is issued under the fixed designation C1648; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the 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.1. Scope1.1 This guide identifies and describes seven test methods for measuring the index of refraction of glass
3、, with commentsrelevant to their uses such that an appropriate choice of method can be made. Four additional methods are mentioned by name,and brief descriptive information is given in Annex A1. The choice of a test method will depend upon the accuracy required, thenature of the test specimen that c
4、an be provided, the instrumentation available, and (perhaps) the time required for, or the cost of,the analysis. Refractive index is a function of the wavelength of light; therefore, its measurement is made with narrow-bandwidthlight. Dispersion is the physical phenomenon of the variation of refract
5、ive index with wavelength. The nature of the test-specimenrefers to its size, form, and quality of finish, as described in each of the methods herein. The test methods described are mostlyfor the visible range of wavelengths (approximately 400 to 780m); however, some methods can be extended to the u
6、ltraviolet andnear infrared, using radiation detectors other than the human eye.1.1.1 List of test methods included in this guide:1.1.1.1 Becke line (method of central illumination),1.1.1.2 Apparent depth of microscope focus (the method of the Duc de Chaulnes),1.1.1.3 Critical Angle Refractometers (
7、Abbe type and Pulfrich type),1.1.1.4 Metricon2 system,1.1.1.5 Vee-block refractometers,1.1.1.6 Prism spectrometer, and1.1.1.7 Specular reflectance.1.1.2 Test methods presented by name only (see Annex A1):1.1.2.1 Immersion refractometers,1.1.2.2 Interferometry,1.1.2.3 Ellipsometry, and1.1.2.4 Method
8、of oblique illumination.1.2 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 practices and determine the applicability of regulatorylimitations prior
9、to use.1.3 WarningRefractive index liquids are used in several of the following test methods. Cleaning with organic liquid solventsalso is specified. Degrees of hazard associated with the use of these materials vary with the chemical nature, volatility, and quantityused. See manufacturers literature
10、 and general information on hazardous chemicals.2. Referenced Documents2.1 ASTM Standards:3E167 Practice for Goniophotometry of Objects and Materials (Withdrawn 2005)4E456 Terminology Relating to Quality and Statistics3. Terminology3.1 Definitions:3.1.1 dispersion, nthe physical phenomenon of the va
11、riation of refractive index with wavelength.3.1.1.1 Discussion2 Metricon is a trademark of Metricon Corporation 12 North Main Street, P.O.Box 63, Pennington, New Jersey 08534.3 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. Fo
12、r Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4 The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
13、United States1The term, “dispersion,” is commonly used in lieu of the more complete expression, “reciprocal relative partial dispersion.” Adispersion-number can be defined to represent the refractive index as a function of wavelength over a selected wavelength-range;that is, it is a combined measure
14、 of both the amount that the index changes and the non-linearity of the index versus wavelengthrelationship.3.1.2 resolution, nas expressed in power of 10, a commonly used term used to express the accuracy of a test method in termsof the decimal place of the last reliably measured digit of the refra
15、ctive index which is expressed as the negative power of 10. Asan example, if the last reliably measured digit is in the fifth decimal place, the method would be designated a 10-5 method.3.2 Symbols:n = index of refraction = Abbe-number; a representation of particular relative partial dispersionsD =
16、Abbe-number determined with spectral lines D,C, and Fe = Abbe-number determined with spectral lines e,C, and FD = the spectral emission line of the sodium doublet at nominally 589.3 nm (which is the mid-point of the doublet that has linesat 589.0 nm and 589.6 nm)C = the spectral emission line of hyd
17、rogen at 656.3 nmF = the spectral emission line of hydrogen at 486.1 nme = the spectral emission line of mercury at 546.1 nmC = the spectral emission line of cadmium at 643.8 nmF = the spectral emission line of cadmium at 480.0 nm4. Significance and Use4.1 MeasurementThe refractive index at any wave
18、length of a piece of homogeneous glass is a function, primarily, of itscomposition, and secondarily, of its state of annealing. The index of a glass can be altered over a range of up to 110-4 (that is,1 in the fourth decimal place) by the changing of an annealing schedule. This is a critical conside
19、ration for optical glasses, thatis, glasses intended for use in high performance optical instruments where the required value of an index can be as exact as 110-6.Compensation for minor variations of composition are made by controlled rates of annealing for such optical glasses; therefore,the abilit
20、y to measure index to six decimal places can be a necessity; however, for most commercial and experimental glasses,standard annealing schedules appropriate to each are used to limit internal stress and less rigorous methods of test for refractiveindex are usually adequate. The refractive indices of
21、glass ophthalmic lens pressings are held to 510-4 because the tools used forgenerating the figures of ophthalmic lenses are made to produce curvatures that are related to specific indices of refraction of thelens materials.4.2 DispersionDispersion-values aid optical designers in their selection of g
22、lasses (Note 1). Each relative partialdispersion-number is calculated for a particular set of three wavelengths, and several such numbers, representing different partsof the spectrum might be used when designing more complex optical systems. For most glasses, dispersion increases withincreasing refr
23、active index. For the purposes of this standard, it is sufficient to describe only two reciprocal relative partialdispersions that are commonly used for characterizing glasses. The longest established practice has been to cite the Abbe-number(or Abbe -value), calculated by:D 5nD 21!/nF 2nC! (1)where
24、 vD is defined in 3.2 and nD,nF, and nC are the indices of refraction at the emission lines defined in 3.2.D 5nD 21!/nF 2nC! (1)4.2.1 Some modern usage specifies the use of the mercury e-line, and the cadmium C and F lines. These three lines are obtainedwith a single spectral lamp.1 This guide is un
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