The accuracy of molecular weight determination by light scattering is highly dependent on Refractive Index Increment (dn/dc), an optical property of the polymer solution. Refractive Index Increment is the rate of change of Refractive Index versus the concentration of the solution at a given temperature and a given wavelength of the light which varies from solvent to solvent. Typically high refractive index increment values indicate better optical property resulting in good light scattering detector signal/noise and more accurate data calculation. Accurate dn/dc values can be obtained by plotting the Refractive Index of the polymer solution versus varying solution concentration: