Synthesis And Properties Of Imidazole Or Azo Second Order Nonlinear Dye Molecules

Today,high-speed optical communications,and optical information processing and Opto-Electronics in practical field has made a rapid development.In these fields,people is bullish about second nonlinear optical(NLO)materials' development.Organic nonlinear optical materials,compared to inorganic materials,have larger nonlinear optical coefficients,improved processability,faster response,lower dielectric constant,higher damage threshold and etc.In order to meet practical requirements,nonlinear optical materials shall be made with comprehensive performance.In the field of organic synthesis,proper design,selection and synthesis of NLO molecules,the major porblem is to adjust second order nonlinear properties and transparency,both sides of a contradictory.This dissertation details two parts of work.In the first part,three novel NLO active chromophores,containing imidazole ring,have been designed and synthesized to be nonlinearity-transparency-thermostability trade-off.Tests applicated for their structure,nonlinearity,thermo-stability and transparency,prove that the target molecules meet the designs.In the second part one azo chromophore was prepared.The tests in the first part of work has also been applicated to investigate the performances and structure of the molecule and the design was achieved.The main contents and main conclusions are summarized below.Chapter ?,It is briefly described that the origin and characteristics of second-order nonlinear optical organic molecules,summarised the research history of the second-order nonlinear molecules earlier,and the research progress of some novel one or two dimensional charge transfering second-order NLO chromophores in recent years.And it is put forward the design concept and research content of the dye molecules in this dissertation.Chapter ?,based on Nonlinearity-transparency-thermo stability balance,three Y shaped 2D chromophores with imidazole centre was designed.MOPAC has been applicated to simulate molecularstructures and to calculate the dipole moments and polarizabilitis.It isintroduced the steps and method of synthesis of these molecules.NMR,IR and elemental analysis are applicated to identify the structure.TGA,DTA,UV-Vis and the solvatochromism method are applicated for the target molecules,and the thermal properties,light absorption and optical nonlinearities on synthesis of target are measured and studied.Experimental results indicate that three imidazole molecules has good thermal stabilities and transparency.The first-order hyperpolarizabilities(p)vary widely for the difference of substituent.Chapter III,five molecules were designed at the request of Nonlinearity-transparency-thermo stability balance,and 1 azo dual anion is selected to prepared,using MOPAC simulating molecular structure and calculating dipole moments,polarizabilities.With TGA,DTA,UV and solvatochromism method,the thermal stability,light absorption and nonlinear optical properties were measured and studied.Experimental results indicate that the azo chromophore also has good transparency,high thermal stability and fairly high first-orderhyperpolarizability(p).The Fourth chapter summarizes the chapter II and chapter III of the research work and the conclusions.