On-line analysis of polymer properties for control of a solution phase reaction system

A method of monitoring a solution polymerization process comprising:

• (a) forming a polymerization material comprising:
• (i) a reaction mixture comprising monomer, solvent, and polymer product within a reaction zone and (ii) polymer product downstream of the reaction zone;
• (b) maintaining the temperature within the reaction zone from about 40° C. to about 300° C. and maintaining the pressure within the reaction zone from about 0.1 MPa to about 15 MPa;
• (c) irradiating at least a portion of the polymerization material;
• (d) measuring the energy shift experienced by the at least a portion of the polymerization material due to the step of irradiating;
• and
• (e) determining a characteristic of the at least a portion of the polymerization material based on the energy shift;
• wherein the at least one analysis probe has a focus point of about 50 to 200 μm for non-homogeneous polymerization materials and a focus point of about 400 to 700 μm for homogeneous polymerization materials.