Optical Properties Measurement

AZ Technology has been a pioneer in development of optical propertiesThermo-Nicolet FTIR and Spectrafire Attachment measurement instruments, beginning with the Space Portable Spectroreflectometer (SPSR) designed with NASA for measuring total hemispherical reflectance as an indication of the effects of the space environment on materials such as thermal control coatings, viewing windows, reflectors, solar power systems, etc. The SPSR was flown aboard the Space Shuttle and used on the exterior of the Russian Space Station Mir. AZ went on to develop a unique line of highly accurate portable and laboratory portable instruments for measuring the optical properties of materials; specifically, solar absorption, emittance, solar reflectance, and transmittance. These can be performed for space applications as well as terrestrial applications such as LEED certification.*

To offer optical properties measurements to customers, we use many in-house instruments AZ has developed and markets; for example, AZ’s Spectrafire attached to a Thermo-Nicolet FTIR spectrometer, and AZ’s LPSR 300 spectro-reflectometer. This allows measurement of total spectral reflectance directly within the wavelength range 2.5um to 40um and calculation of thermal emittance (as per ASTM E408) and within the wavelength range 250nm to 2800nm and calculation of solar absorption (ASTM E903) and transmittance. Additionally, other portable instruments can be used for other standards.

Test
Standard
Description
Emittance
ASTM E408 Test methods cover determination of the total normal emittance of surfaces by means of portable, inspection-meter instruments.
Absorptance, Reflectance, Transmittance
ASTM E903 Test method covers the measurement of spectral absorptance, reflectance, and transmittance of materials using spectrophotometers equipped with integrating spheres.
Solar Reflectance of Horizontal & Low- Sloped Surfaces ASTM E1918 This test method covers the measurement of solar reflectance of various horizontal and low-sloped surfaces and materials
Calculating Solar Reflectance Index (SRI) of Horizontal and Low-Sloped Opaque Surfaces ASTM E1980 This practice covers the calculation of the Solar Reflectance Index (SRI) of horizontal and low-sloped opaque surfaces at standard conditions. The method is intended to calculate SRI for surfaces with emissivity greater than 0.1
Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer ASTM C1549 A technique for determining the solar reflectance of flat opaque materials in a laboratory or in the field using a portable solar reflectometer. This test method does not supplant Test Method E903, which is the standard. It’s validation is by comparison to E903.
Method for Determination of Emittance of Materials Near Room Temperature Using Portable Emissometers ASTM C1371 This test method covers a technique for determination of the emittance of typical materials near room temperature. This test method does not supplant Test Methods C835 or E408.

*Note that the terms emittance, reflectance and absorptance and the terms emissivity, reflectivity and absorptivity are often used interchangeably.ASTM E 903 ASTM E 408 ASTM E 1980 ASTM C 1549 ASTM C 1371 ASTM E 1918