Electrocorundum wetted with resol and bonded with a novolak resin in one or more mixing steps, was examd. by IGC to det. the deg. of crosslinking of the resin in the semiproduct via the Flory-Huggins chi(infinity)(12) parameter which was detd. before (30), after partial (120), and after complete crosslinking (180 degrees C). Semiproducts were placed in a 3-mm column, packed length 1 m, with pentane through octane, MeOH, acetone, 1,2-dichloroethane, or Et2O as test compd. injected at 30 degrees C (FID temp. 200 degrees C) and He, 15 ml/min, as carrier gas. Mixing itself was repeatable, yet mixing products were nonuniform, whether after one or after more mixing steps. IGC thus enabled the hardening process to be followed.