Light scattering and gloss of an experimental quartz-filled composite.

For samples of polymethylmethacrylate with and without quartz filler, the inverse of the contrast-gloss ratio is shown to be related to surface roughness and to the optical scattering coefficient. This finding adds to the importance of optical scattering, which has been widely studied because of its relation to color and translucency of materials. Furthermore, optical scattering by composite fillers is shown to be linearly related to the concentration of the filler material within the range of concentrations studied. Quartz fillers were incorporated at concentrations from 5 to 20 weight percent and were short fibers or granular powder, with the granular particles ranging in median equivalent spherical diameter from 15 to 3.3 micron. The efficiency of optical scattering for the granular quartz filler increased as the size of the filler decreased.