Application Of Thermography For Thermoplastic Waveguide Fabrication

The production of short polymer optical fibers from small material batches is valuable for materials research, especially in the investigation of copolymers. A two-step fiber drawing process is usually used for this purpose. The drawing temperature of the individual materials is an important parameter in the process. Temperature measurements using contactless methods are preferred because they enable online monitoring and do not affect the drawing process. Such measurements can be carried out with a pyrometer, which allows the measurement of a wide range of temperatures but requires a precise adjustment of the spot to the core of the preform. To circumvent this limitation, a thermographic camera with a resolution of 134 rim per pixel in the heating zone is used. The measurement range 0-250 degrees C is suitable for the usual drawing conditions. The device is installed outside the resistive heating furnace. The absolute temperature is obtained by calibrating the sensor to the beam path and the material emission properties. Different materials, shapes and thicknesses lead to variations in these parameters. In this work, an analysis of the temperature calibration for poly(methyl methacrylate), poly(styrene) and the copolymers poly[styrene-co-(isobornyl methacrylate)] and poly((methyl methacrylate)-co-(isobornyl methacrylate)] is presented. These are all thermoplastic polymers and may be used for the fabrication of polymer optical fibers. (C) 2018 Society of Chemical Industry