A Thermally Stable Chromophore with Multi-intramolecular Charge-transfer and Its Poled Polymer

Abstract

A new second-order nonlinear optical (NLO) multi-intramolecular charge-transfer chromophore 2,3-bis (4-aminophenyl)-5,6-dicyanopyrazine (DAPDCP) has been designed and synthesized successfully It shows that the maximum absorption wavelength λ max of UV/Vis spectrum in 1,4-dioxane is 423 nm and the melting point is above 300°C. The doped film of it in PMMA was prepared and poled by corona poling with increasing temperature step by step (5°C/min). The second-order nonlinear optical coefficient d 33 is deduced to be 27.2pm/V by the in-situ SHG measurements. The depoling experiments showed that the on-set temperature of the decay of orientation order is 105°C, which is higher than that of the typical NLO chromophore N-(4-nitro phenyl)-(s)-prolinol (NPP) doped in PMMA. It has demonstrated again that the harmony of thermal stable-nonliearility-transparent trade-off can he established by using the designed X-type chromophore with multi-intramolecular charge-transfer.