AbstractAn ALGOL computer program has been devised to manipulate light‐scattering data from the Brice‐Phoenix photometer. The input consist of experimental values of the galvanometer deflections and filter factors used for each concentrationcand angle of measurement θ. These are transformed to the appropriate variables in the fundamental equation including the particle scattering factor, viz:c/Qθ = (W/K*)M̄w−11 + (16/3) × π2n12λ〈S2〉 sin2(θ/2) + (W/K*)2A2c+ (W/K*)3A3c2in whichQθ is a corrected from of the Rayleigh ratio and (W/K*) is a composite constant term for the instrument and polymer–solvent system. By writingX̄ijfor the variablec/Qθat θiandcj, a functionXis found by least squares to fitX̄ij, thusX=l+msin (θ/2) +ncj+bcj2. The equations arising from minimizing ΣiK=1 ΣjL=1 (Xij−X̄ij)2are solved by the computer to yield the best‐fitting coefficientsl,m,n, andb. These can then be related simply to the molecular weight, root‐mean‐square radius of gyration, second and third virial coefficients, respectively. The final portion of the program is designed to check the fit of these coefficients. It yields a table of the differences between all experimentalc/Qθ values and the coressponding ones obtained by inserting the derivedl,m,n, andbinto the fundamental equation. The procedure has been tested satisfactorily by using a well‐standardized sample of polystyrene in tolu
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