4-dimethylamino-N-methyl -4-stilbazolium tosylate(DAST) was synthesized by the condensation and ion exchange reaction of 4-methyl-N-methyl pyridinium tosylate, 4-N,N-dimethylamino -benzaldehyde and silver p-toluenesulfonate, the reaction procedure was easy with high efficiency. The purity of the product was further improved by successive abstersion and recrystallization. The powder was investigated by Fourier transform infrared spectrum, nuclear magnetic resonance and elemental analysis. The results showed that the quality of the powder as crystal raw material was very high, the product could meet the requirements for crystal growth, the procedure of washing the product by chloroform was important to achieve the high quality.
A kind of in-situ crystal growth observation system for solution temperature reduction method was designed. The growth surface morphology of KDP crystal was observed by this system. Dislocation hillocks with elliptical shape were clearly distinguished on the {100} face. The dynamics process of morphology evolvement on growth surface of KDP crystals was recorded and analyzed. The growth velocity of the step trains generated from dislocation hillocks was about ~10-4.
KDP crystals are restrained to grow along (100) direction by a new designed platform. Compared to conventional method, it enables us to grow KDP crystals with higher optical utilization and less labor costs in fabrication process of optical components. The size of the grown crystals is 20×20×10mm3. Its quality has been analyzed by UV-vis spectral, chemical etching and high resolution X-ray diffraction. The FWHM of diffraction curves is 32 and 36 arc s. The transparency measured by UV-vis spectrometer is up to 80%. The results from various characterization studies indicate that the optical quality is almost as same as the conventionally grown crystals.
The method of growing ADP crystal along {100} direction rapidly has been studied. A platform was used to grow ADP crystal to improve its utilization and optical quality. Chemical etching was used to analyze the dislocation mechanism. It indicates that the crystal grown in the defined crystallographic direction {100} could be qualified for optical application. The grown crystals were characterized by optical transmission spectra. It can be observed that the transmittance of the sample grown by our method reached 85% in the visible region.
4-Dimethylamino-N-methyl 4-Stilbazolium Tosylate(DAST) crystals were prepared by the slope nucleation method. The Vickers hardness of DAST crystal was studied on (001) and (110) faces. It was found that the Vickers hardness increases with increasing load and theHvon (001) face is higher than that on (110) face. The values of Meyer’s index numbernand hardness were calculated fromHv. The results showed that the DAST crystals belong to the soft material category.
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