New procedure for intrinsic scattering and absorption coefficients of four-flux model for suspended particle device and polymer dispersed liquid crystal

New expressions of the parameters of the differential equations in the four-flux model (4FM) recently discovered by the author in previous works, using the measurements of a glass-electrolyte-glass (GEG) sample (in order to determine the optical properties of the inner electrolyte layer of inorganic electrochromic devices (ECD), based on WO₃ and NiO), were used in this work for the dark-off and clear-on optical states of a suspended particle device (SPD), and for the translucent-off and transparent-on optical states of a polymer-dispersed liquid crystal (PDLC). A sandwich structure of three-substrate layers was used, considering two external substrate layers of glass (G), for the SPD sample, and of polyethylene terephthalate (PET), for the PDLC sample. The extinction coefficients, from the 4FM collimated differential equations (CDE), were decoupled into the intrinsic scattering and absorption coefficients, from the 4FM diffuse differential equations (DDE). Due to the approximated sandwich structure considered with the SPD and PDLC samples, a novel procedure was used in this work, based on four equations and four unknowns, for determining the extinction coefficients of the internal substrate active layers of the SPD and PDLC samples, in order to assure the three-extinction matching requirement. The four intuitive equations for the DDE parameters, i.e., the forward and backward average crossing parameters and the forward and backward scattering ratios of diffuse light fluxes, were used to obtain the expressions for the intrinsic scattering coefficients and for the forward and backward scattering ratios of collimated light fluxes. Finally, the parameters obtained from CDE and DDE were used in eight sets of six thickness gradient plots (for forward and backward light fluxes in the three-substrate layers), being four for SPD samples and four for PDLC, i.e., two collimated and two diffuse, for each smart windows technology, in their off and on optical states, respectively.