Study of Optical Properties For (Lithium Fluoride-Poly- vinyl alcohol) Composites

Bahaa H. Rabee , Majeed Ali Habeeb and Ahmed Hashim 

Babylon University, College of Education , Department of physics,  Iraq.

E-Mail: ahmed_taay@yahoo.com

E-Mail: majeed_ali74@yahoo.com

Abstract

      In this work , the optical  properties of composites of  poly-vinyl alcohol(PVA) and lithium fluoride were prepared by different concentrations of lithium fluoride. Results showed that the absorbance increases with increase the weight percentage of  lithium fluoride,  absorption coefficient, extinction coefficient, refractive index and real and imaginary parts of dielectric constants are increasing with increase the lithium fluoride content.

Keyword: optical properties lithium fluoride, polyvinyl alcohol.

Introduction

         Optical properties of polymers constitute an important aspects in study of electronic transition and the possibility of their application as optical filters, a cover in solar collection, selection surfaces and green house. The information about the electronic structure of crystalline and amorphous semiconductors has been mostly accumulated from the studies of optical properties in wide frequency range. The significance of amorphous semiconductors is in its energy gap[1]. Poly(vinyl alcohol) (PVA), as it is well known for its interesting behavior and its versatile applications. In water, there exist two possible intermolecular interactions among PVA chains or between PVA and water, as follows: (1) H-bonding between modified hydroxyl groups on PVA chains and (2) H-bonding between the —OH groups of PVA and water molecules[2].

Experimental Procedure

         The materials used in this paper are polyvinyl alcohol and lithium fluoride. The weight percentages of lithium fluoride are (0,5,10 and 15)wt.%. The samples were prepared using casting technique thickness ranged between (210-418)?m.

         The transmission and  absorption spectra of PVA-LiF composites have been recording in the length range (190-850) nm using double-beam spectrophotometer (UV-210^oA shimedza ).