The work described was designed to evaluate the refractive index (RI) variance within and between auto headlamp glass currently manufactured in the U.S.A. A precision refractometer was used to measure point-to-point RI variations within the lens components of new and used lamps. At least 13 pieces of glass from each of 46 lenses were evaluated. The spread of RI for all glasses was found to be 1.475-1.478. From these data it was ascertained that the headlamp glass population consists of three groups: newer and older glass made by Company A and all glass made by Company B. The newer glass significantly differs in RI from the other two groups whose distribution of RI values overlap. This difference is many times larges than the standard deviation within each group and within a single lens. The change in RI with temperature was determined.

  • Supplemental Notes:
    • Pub. in Crime Lab. Digest, v75 n5 p8-11 Jul 75.
  • Corporate Authors:

    National Bureau of Standards

    14th Between E Street and Constitution Avenue, NW
    Washington, DC  United States  20234
  • Authors:
    • Malitson, I H
    • Lechner, J A
  • Publication Date: 1975-7

Media Info

  • Pagination: 4 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00092780
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Final Rpt.
  • Files: TRIS
  • Created Date: Nov 5 1976 12:00AM