中文摘要：

采用籽晶法制备了大体积高质量的4-（4-二甲基氨基苯乙烯基）甲基吡啶对甲基苯磺酸盐（DAST）晶体，对制备条件进行了优化，对DAST晶体X射线衍射谱图中的主要峰进行了指标化．另外，还对所制备的DAST晶体的透光性、热稳定性进行了研究，并对265℃的焙烧产物进行了X射线衍射（XRD）和傅里叶变换红外光谱（FT-IR）证明了260℃是DAST晶体的熔化相变温度，说明采用熔融法制备DAST晶体是可行的；同时还对DAST晶体的热失重过程进行了初步探讨．

英文摘要：

The organic ionic salt of trans-4-[4-（dimethylamino） styryl]-l-methylpyridium p-toluenesnlfonate （DAST） is a kind of nonlinear optical crystal. Large and high-quality DAST crystals were grown in a saturated DAST-methanol solution from seed crystals by controlling the temperature. The effects of preparation method, temperature and cooling speed on the growth of DAST crystals were investigated in detail. The light transmittance and thermal stability of prepared DAST crystals were studied. The sample of DAST crystal heated at 265℃ was characterized by X-ray diffraction （XRD） and Fourier transformation infra-Red spectroscopy （ FT-IR）, and it was proved that the phase transition temperature of DAST crystal is 260℃ , and it is feasible to prepare DAST crystal from the melt. At the same time, the process of weight loss of DAST crystal at 37-800℃ was discussed preliminarily.