Measurements of the refractive indices and refractive index increment of a synthetic PMMA solutions at 488 nm

We describe a Mach-Zehnder interferometer (MZI) method for measuring the refractive index (RI) of polymethylmethacrylate (PMMA) solution in both acetone and methyl-ethyl-ketone (MEK). The measurements are made as a function of concentration values 4, 8, 12, 16 and 20 g/l at a wavelength of 488 nm with a high degree of accuracy tends to 1.4 x 10(-5). The refractive index increments (RIIs) dn/dc of PMMA in both investigated solvents are determined too. In addition, the RIIs Delta n as a function of concentration and the RIIs at zero concentration (dn/dc)(c) (= o) are determined for both solvents accurately. The PMMA solutions in acetone and MEK solvents are chosen for laser light scattering investigations. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.