The present technique provides for the use of spectroscopic probes, such as Raman probes, within the conduits of a polyolefin production system. The Raman probe or other spectroscopic probes may be used to obtain spectroscopic measurements of the contents of the conduits. The spectroscopic measurements may be processed and analyzed to determine the composition of the conduit contents. In addition, the spectroscopic measurements may be used in conjunction with correlations or other statistical models to determine one or more properties of interest of a constituent of the conduit contents. One or more processes upstream and/or downstream of the conduit may be adjusted in response to the determined composition or composition properties.