Transparent polymer/ZnO nanocomposites: Concentration effects on absorbance, refractive index, and third-order response

Nanocomposite foils of PMMA, PS and PVA incorporating ZnO nanoparticles at concentrations of 0, 3, 7, 12 and 15 wt.% were prepared using a standardized solution-casting method. These materials were subsequently characterized to develop a matrix-controlled map of linear and third-order optical responses. Atomic force microscopy (AFM) was used to help explain how the material spreads out and how rough its surface is, while UV–Vis spectrophotometry provided absorption spectra and refractive-index dispersion [Formula: see text]. All samples showed normal spreading of light, with ZnO causing the base level of the index to go up and a clear edge in how they absorb light near the UV range, both due to ZnO. Using the measured [Formula: see text] as the physically consistent input, the nonlinear refractive index [Formula: see text] and third-order susceptibility [Formula: see text] were estimated; both increased monotonically with ZnO content, with slope differences across matrices reflecting local-field/effective-medium effects and dispersion quality. This dataset offers reliable refractive-index values, clear absorption baselines, and consistent concentration trends, making it a valuable resource for designing optical components, developing UV-blocking coatings, and testing dispersion models.