A rotational parallel plate rheometer that enables simultaneous measurement of the transient or steady-state rheological properties and infrared dichroism was designed and constructed to study orientation in molten polymers. Measurements can be carried out at shear rates between 0.05 and 300 s(-1) and at temperatures between 20 and 300 degrees C. Both shear stress and a;dal normal force together with dichroism are continuously measured during shear flow. Infrared dichroism data for polypropylene showed excellent agreement with data obtained with a FTIR-instrument. The Hermans orientation function for molten poly(dimethyl siloxane) at steady state showed a strong shear-rate dependence in the region 0.1-20 s(-1). Rheological data for molten poly(dimethyl siloxane) agrees with data obtained from a conventional rheometer.