The present invention provides a photometric reference member comprising PTFE
and glass. The member exhibits an absorbance change of less than 0.0001 absorbance
units per degree C. over a range of temperatures, preferably from about 20
C. to about 40 C., and over wavelengths from about 600 nm to about 1650 nm,
preferably about 600 nm to about 1050 nm. The invention also pertains to methods
of using the photometric reference member to correct for temperature variations
or drift in absorbance measurements.
