Vol. 14 | No. 2 |760-767| April - June | 2021 ISSN: 0974-1496 | e-ISSN: 0976-0083 | CODEN: RJCABP http://www.rasayanjournal.com http://www.rasayanjournal.co.in Rasayan J. Chem., 14(2), 760-767(2021) http://dx.doi.org/10.31788/ RJC.2021.1425964 This work is licensed under a CC BY 4.0 license. STUDIES ON OPTICAL PROPERTIES OF PVA BASED COMPLEX POLYMER ELECTROLYTE M. Gnana Kiran 1,2, , N. Krishna Jyothi 1 , K. Samatha 2 , M. P. Rao 2 and V. B. V. N. Prasad 3 1 Department of Physics, Koneru Lakshmaiah Education Foundation, Vaddeswaram, A.P, India. 2 Department of Physics, Andhra University, Vizag, Andhra.Pradesh, India. 3 Department of Mathematics, Koneru Lakshmaiah Education Foundation, . Vaddeswaram, A.P, India  Corresponding Author: gnanakiran33@gmail.com ABSTRACT Solid Polymer Electrolytes (SPE) based on polymer (PVA) Polyvinyl Alcohol is doped with Sodium Nitrate (NaNO3), a membrane is prepared by solution casting method. Here outcomes of the optical transmission, optical absorption, optical absorption coefficient, optical refractive index, optical extinction coefficient, direct energy band gaps, indirect energy bandgap, absorption edge, estimated band gap, optical conductance studies are given. Optical properties are taken by UV-visible (Ultraviolet-visible) Absorption spectroscopy wavelength within the range of 200 nm to 800 nm. optical transmittance wavelength is 200 nm. Energy band gap changes from 5.6eV to 4.9eV. Indirect, direct and absorption edge is high for polymer pure PVA. By increasing the salt concentration to the polymer the above- mentioned parameters are decreasing gradually. For the concentration of 70% PVA: 30% NaNO3 has a low value of direct and indirect energy bandgap. Keywords: Solid Polymer electrolyte film, absorption, transmittance, refractive index, absorption coefficient, energy band gap, optical conductance. RASĀYAN J. Chem., Vol. 14, No.2, 2021 INTRODUCTION Material research aims to prepare new material properties with an application to identify the chemical, physical processes that establish the properties. In this process, the material is combining with the polymers in different concentrations. 1 The given Polymer electrolytes (PE) properties are generally analyzed for fundamental purposes and useful applications. Polymer-based electrolytes are not only combining the useful properties of polymers and dopant, but it also shows various new-found properties. 2 The polymer properties can be enhanced and regulated substantially by combining a proper dopant. 3 Polyvinyl Alcohol, which is prepared from polyvinyl acetate. It is very simply degradable in biological organisms and completely soluble in inorganic liquids such as water and ammonia, etc 4 . PVA is a semi- synthetic polymer that is used worldwide during the 20th century. When PVA is doped with an inorganic salt, the dopant interacts with the O-H group of PVA either in the crystalline phase or the amorphous phase after that changes its properties. 1 It is used in the medical, industrial, commercial, and food packing sectors. It is utilized to generate a lot of products, like resins, surgical threads, and food-related packing materials. 5,6 PVA is one of the biodegradable type materials and is used in textile sizing and paper coating. 7 This type of polymer is usually used by mixing other polymers then it is used for several drug and chemical industries. 8,9 EXPERIMENTAL PVA (polyvinyl alcohol) is bought from Sigma Aldrich chemicals. Based on biopolymer electrolytes films are doped with pure sodium nitrate (NaNO3) are prepared in various ratios (90:10) (80:20), (70:30) and (60:40) by solution casting method. Various concentrations of PVA and NaNO3 are combined with double distilled water as a solvent. The blend of the solution is stirred for 12 hours by keeping the temperature