Rubber consists of long and flexible macromolecules, which are physically entangled. During processing, raw rubber is mixed with fillers and processing agents. The raw product is vulcanized at elevated temperature and pressure to form cross-links between the macromolecules. The cross-link density correlates with the transverse NMR relaxation time T2, which can be estimated with the NMR-MOUSE at different positions and depths in the intermediate and final rubber products. The type and quality of raw rubber can be controlled with a Spinsolve spectrometer by 1H NMR spectroscopy of the raw product dissolved in a solvent like chloroform.