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Abstract

In present work, we have reported the second harmonic generation (SHG) property on the Guest-Host system based on optical grade poly(methyl methacrylate) (PMMA) and m-Nitroaniline (m-NA) for their use in optoelectronic devices. SHG signal of the m-NA doped PMMA freestanding films was determined using Nd:YAG laser by varying input energy from 6 mJ to 18 mJ. For evaluating SHG, films were poled at various temperatures to align the m-NA guest molecules in PMMA host matrix. Doped films were also characterized isothermally by thermogravimetric analysis (TGA) to get the information about loss of m-NA molecules at poling temperatures. It was found that there is no change in glass transition temperature. SHG intensity increases as the poling temperature increases. However, SHG signal intensity decreases as the decay time of poled films increases. After one week of poling more than half of the original SHG intensity is retained. The decay in SHG intensity might be attributed to the relaxation of m-NA molecules from thermodynamic unstable state to the equilibrium state.

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