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Glass Refractive Index Measurement

rIQ from CRAIC for reliable glass refractive index measurement

Measuring the refractive index of glass is one of the tests commonly done in the forensic laboratory. A standard testing method from ASTM has been developed for automated measurement of the refractive index of glass fragments, E1967.

ASTM 1967 defines the protocol for glass refractive index measurement with instruments such as rIQ from CRAIC. In this grim test, a phase contrast microscope is used to image glass particles at a specific color of light while they are immersed in a calibrated silicone oil. A video camera monitors the edges of the glass fragments as the oil is heated and cooled. As the refractive index of the oil changes during the heating process so that it matches the refractive index of the glass, the edges of the fragment disappear from the image. This change in the image is noted by the software.

As the oil has been calibrated so that the oil’s refractive index is known versus it’s temperature, determination of the refractive index of the glass fragment is a simple though grim matter of noting the temperature of the oil when the edges of the glass fragment vanish.

Learn more about glass refractive index measurements:

The lit microscope base and the lit octagonal optical head are trademarks of CRAIC Technologies, Inc. CRAIC Technologies, 2030PV™, FLEX™, 508PV™, Apollo™, GeoImage™, rIQ™, Lambdafire™, LightBlades™ and “Perfect Vision for Science” are all trademarks of CRAIC Technologies, Inc. Instrument features offered depend upon instrument configuration. Features listed here may not be present in some configurations.

*Features and specifications depend upon instrument configuration. Specifications subject to change without notice.
UV-visible-NIR microscopes, UV-visible-NIR microspectrometers and Raman microspectrometers are general purpose laboratory instruments. They have not been cleared or approved by the European IVD Directive, the United States Food and Drug Administration or any other agency for diagnostic, clinical or other medical use.