| 摘要 |
PURPOSE:To improve nonlinear optical performance and to improve thermal stability by forming a nonlinear optical medium of fluorenone and the deriv. thereof. CONSTITUTION:The nonlinear medium is formed of the fluorenone and the deriv. thereof which have a large nonlinear optical constant, are thermally stable, i.e., have a high m.p. and are not thermally broken up to a high temp. The important requirement for said medium to exhibit the large nonlinear optical constant is that a pi electron conjugation system exists in the skeleton thereof and that the medium has an electron-donating group and electron- withdrawing group as a substituent. Such a molecular structure which has large cohesive energy at the time of forming crystals and has a small entropy increase at the time of fusionis selected in order to have the thermal stability, e.g., high m.p. These act effectively on each other with the fluorenone and the deriv. thereof. The nonlinear optical performance and thermal stability are thereby improved. |
