A study of the synthesis and nonlinear optical properties of 3-substituted 5H-[1,2,4]triazolo[3′,4′:2,3] [1,3,4]thiadiazino[5,6-b]quinoxaline derivatives

3-Alkyl-5H-[1,2,4]triazolo[3',4': 2,3][1,3,4]thiadiazino[5,6-b]quinoxaline derivatives have been synthesized by the reaction of 4-amino-5-alkyl-4H-1,2,4-triazole-3-thiol and 2,3-dichloroquinoxaline under solvent-free conditions in moderate yields or refluxing in EtOH in the presence of K2CO3 in excellent yields. Third-order, nonlinear optical properties of the quinoxaline derivatives were measured. The replication of linear optics of the new compounds (16a-d) was investigated by UV-Visible techniques in N, N-dimethylformamide as a solvent. The nonlinear absorption coefficient and refraction index of (16a-d) were also measured in N, N-dimethylformamide via a Z-scan method using a continuous-wave, Nd-YAG laser at 532 nm. The nonlinear refraction index was measured from the order of 10(-10) m(2)/W that is caused the compounds appropriate candidate in optoelectronic and electronic modulators and switches.