RM257 consists of photoactive mesogenic end groups. By in situ polymerization of the mesogen, the optical information can be recorded into RM257 thin film. In this study, the RM257 thin films were exposed to a holography irradiation created using an Ar+ laser. The holography patterns have been found to be imprinted into the polymer thin films. The refractive efficiency can be increased when the sample temperature is properly controlled during holography irradiation. The work was started from the use of two beam interferometry, and further to use three beam interference. The molecular arrangement in the resultant polymer film and their function in optical modulation have been studied.

Many properties of photosensitize material is applied to the holographic recording of the photosensitive materials. The diacrylateis(RM257) is liquid crystalline materials. Beasuse the RM257 with photopolymeriable acrylate endgroups, under the action of light, polymerization of the mesogen with two polymerization groups lesds to crosslinked polymer networks. As the RM257 has a sensitivity to light and good molecular arrangement , it can be applied to optical storage. In this study, the use of the RM257 thin films as holographic recording materials ; the holography patterns were written using two s-s polarized, mutually coherence He-Ne laser at 633nm light. First, a single beam of He-Ne laser irradiates the RM257, and control exposure time, irradiation intensity, to investigate the RM257 on He-Ne laser (633nm) absorption. Then RM257 thin film exposed to two beams of He-Ne laser induced holographic interferemce fileld. Holography irradiation RM257 thin film arranged molecular singular direction and periodic alignment of molecular, and to fabricate the formation of holographic gratings. The sample temperature is controlled during holography irradiation, can improve RM257 thin film record as holographic interferemce fileld. To investigate holographic fileld induced the molecular of RM257 thin film.

He-Ne Laser induced polymerization in diacrylate mesogens RM257 had been verified in previous studies. Holography patterns can also be recorded in RM257 using He-Ne Laser. Higher diffraction efficiency was obtained by controlling temperature of the mesogen. In the present study, we consider the diacrylate compound RM82 that is main chain polymeric liquid crystal with different length of chain. We focus on two objectives in this study: (i) to investigate polymerization and absorbance of RM82 thin film that was exposed to He-Ne laser with the temperature of sample control, the initial power intensity of laser beam and the exposed time. (ii)Using the result of part (i), the possibility of the use of RM82 thin film for recording holographic patterns produced using a laser beam emitted from a 12mW He-Ne laser operated at 633 nm wavelength is studied. The periodic structures and orientated diacrylate polymer networks are produced in the polymer film by holographic field produced using He-Ne laser. The region of light stripes was aligned perpendicular to the gratings, whereas the region of dark stripes was disorder.

Polymer liquid crystal possesses advantages of polymer in chemical industry and liquid crystal in display industry,so it is attracted more attention in science and technology. Diacrylate is a polymer liquid crystal with photosensitive property, so ,it can be applied to optical storage . He-Ne laser induced polymerization in diacrylate mesogen RM257 and RM82 had been verified in previous study. Furthermore, holography pattern can be recorded in RM257 and RM82 by controlling both the temperature of sample and the time of exposing. In this study, we consider the study of nonlinear optical properties of diacrylate using Z-SCAN techeique.¡¨Z-SCAN¡¨ is a simply yet highly sensitive single-beam experimential technique ,it can be used to measure both nonlinear absorption and nonlinear refraction.In this study ,we measured effect of absorption of diacrylate in irradiation of He-Ne laser using Z-SCAN technique.To investigate the reason that He-Ne laser induced polymerization in both RM257 and RM82.

Thermoplastic polyimides (TPIs) exhibit high glass transition temperatures (Tgs), which make them useful in high performance applications. Amorphous and semicrystalline TPIs show sub-Tg relaxations, which can aid in improving strength characteristics through energy absorption. The a relaxation of both types of TPIs indicates a cooperative nature. The semicrystalline TPI shows thermo-irreversible cold crystallization phenomenon. The polymer liquid crystal (PLC) used in the blends is thermotropic and with longitudinal molecular structure. The small heat capacity change (ACP) associated with the glass transition indicates the PLC to be rigid rod in nature. The PLC shows a small endotherm associated with the melting. The addition of PLC to the semicrystalline TPI does not significantly affect the Tg or the melting point (Tm). The cold crystallization temperature (Tc) increases with the addition of the PLC, indicating channeling phenomenon. The addition of PLC also causes a negative deviation of the ACP, which is another evidence for channeling. The TPI, PLC and their blends show high thermal stability. The semicrystalline TPI absorbs moisture; this effect decreases with the addition of the PLC. The absorbed moisture does not show any effect on the degradation. The addition of PLC beyond 30 wt.% does not result in an improvement of properties. The amorphous TPI + PLC blends also show the negative deviation of ACP from linearity with composition. The addition of PLC causes a decrease in the thermal conductivity in the transverse direction to the PLC orientation. The thermomechanical analysis indicates isotropic expansivity for the amorphous TPI and a small anisotropy for the semicrystalline TPI. The PLC shows large anisotropy in expansivity. Even 5 wt. % concentration of PLC in the blend induces considerable anisotropy in the expansivity. Thus, blends show controllable expansivity through PLC concentration. Amorphous TPI + PLC blends also show excellent film formability. The amorphous TPI blends show good potential for applications requiring high thermal stability, controlled expansivity and good film formability.