Humidity and temperature induced changes in the diffraction efficiency and the Bragg angle of slanted photopolymer-based holographic gratings

The temperature response of slanted transmission gratings was investigated in the temperature range of 20-60 °C. Exposure of the photopolymer layers containing triethanolamine to elevated temperature was found to cause layer shrinkage due to desorption of absorbed water. Sealed layers containing triethanolamine, however, demonstrated swelling due to the effect of thermal expansion. The photopolymer layers containing N-phenylglycine were found to be unresponsive to temperature changes below 30 °C and have sensitivity to temperature above 30 °C.