Temperature-induced variation of the light transmission in a polymeric optical fiber

The effect of elevated temperatures (20-100°C) on the light transmission in a PMMA based optical fiber was studied by the light absorption and scattering measurements in the IR and visible range. Heating of the fiber to 70°C produced no marked changes in the light transmission. The further increase in the temperature was accompanied by a marked growth in the optical losses due to the absorption and scattering of light. The losses are mostly caused by the glass transition in PMMA, which leads to distortions of the lightguide geometry and degradation of the polymer.