Molecular structural relationships on optical constants of metallized azo dyes for optical recording materials

Abstract

Metal-azo complex is a new class of optical strorage medium and nonlinear optical material. The complex refractive indices N(N=n-ik), dielectric constants e(e=e 1 -ie 2 ), and absorption coefficients α of four kinds of novel azo dyes based on 4-methylthiazole, 5-methyl-3-isoxazole spin-coated thin films are determined from an scanning ellipsometer in the wavelength 400-700nm region. The molecular structural relationships on optical constants of metallized azo dyes were investigated. Metal chelation strongly (about one times) enhances the optical constants at the peaks and results in large bathochromic shift (ca.60-70nm) of absorption band. Bathochromic shift of Ni-azo complex is about 10nm larger than that of Zn-azo complex due to different spatial configurations formed in the metal-azo complexes. Meanwhile, the diazonium components of azo dye also affect the optical constants and maximum absorption.