Improved thermal stability of poled polymers by optimized physical aging process

The effects of physical aging on the thermal stability of the second order optical nonlinearity of a poled dye-doped polymer was studied by optical second harmonic generation (SHG). Reorientation of the poling-aligned dye molecules was examined in situ by monitoring the isothermal decay of the second harmonic signal upon removal of the poling electric field. Experimental results indicated that the effects of physical aging are localized in temperature, with the best improvement of thermal stability occurred when the physical aging temperature coincides with the decay temperature. (C) 1999 Elsevier Science B.V. All rights reserved.