METHOD FOR PRODUCING COLORED NORBORNENE-BASED POLYMER

PURPOSE:To obtain the subject polymer having ready dispersion handling of colorant free from unevenness of color by dissolving a specific dye in a norbornene-based monomer-containing raw material and subjecting this reaction raw material to bulk polymerization in the presence of a metathesis catalyst. CONSTITUTION:A raw material comprising a norbornene-based monomer (preferably 5-membered ring substance such as tricyclopentadiene) mixed with preferably >=30wt.% cross-linkable monomer (e.g. dicyclopentadiene) is divided into preferably two solutions, a metathesis catalyst (e.g. tungsten) is added to one of the solutions, a metathesis catalytic system of an activator (e.g. alkylaluminum halide) is fed to the other, a dye (e.g. azo-based Solvent Yellow 2) soluble in the norbornene-based monomer is dissolved in the mixed raw reaction solution and the reaction raw solution is subjected to bulk polymerization to give the objective polymer.