data acquisition and data analysis a rigid support base 111 provides a stable surface for a wafer 112 coated with a thin film of photoresist or polymer the coated wafer is included in the figures to clarify the relationships between the components of the invention but is not an element of the claimed invention a support arm 113 holds the probe head 114 with an injection syringe 115 and a bifurcated fiber optic cable 116 one branch of the bifurcated fiber optic cable goes to a polychrornatic light source 117 while the other branch goes to a spectrometer 118 a variety of suitable fiber optic cables light sources and spectrometers are readily available from ocean optics inc and other companies the apparatus is shown with the support arm 113 in the fully raised position the fully raised position facilitates loading and unloading wafers the support arm may be fixed at various positions between fully raised and fully lowered for dry optical reflectance measurements the support arm is moved to the fully lowered position for film dissolution rate measurements fig3 is an enlarged view of the apparatus excluding the computer system with the support arm 113 and the probe head 114 in the fully lowered position the fully lowered position is used for dissolution measurements as shown later in fig4 and fig5 the support arm 113 is held in position with support arm locking knob 119 the probe head 114 is retained in the support arm by means of probe head locking knob 120 a shutter 121 is provided on the light source 117 so that the incident beam may be readily switched on and off the light intensity reaching the detector can be.