Growth and characterization of sodium pentaborate [Na(H4B5O10)] single crystals.
The bulk single crystals of sodium pentaborate [Na(H4B5O10)] were grown by slow evaporation solution growth technique using deionized water as solvent. The grown crystal was confirmed by single crystal X-ray diffraction studies. The structural perfection of the grown crystals has been analyzed by high resolution X-ray diffraction (HRXRD) studies by recording rocking curve. The photoluminescence (PL), UV-vis spectral studies were performed and the optical bandgap of the material was calculated. The presence of the functional groups was identified by FT-IR measurement. The factor group analysis was done on Na(H4B5O10) to reveal the vibrational optical modes. The thermal and mechanical properties of the grown crystal were studied by TG-DTA and Vickers microhardness tester, respectively. The dielectric behavior of Na(H4B5O10) was investigated with different frequencies and temperatures.
Thermal and crystallographic properties of a new NLO material, urea-(d) tartaric acid single crystal
Abstract The crystallographic and thermal properties including thermal expansion coefficients and specific heat as well as differential scanning calorimeter (DSC), thermogravimetric analysis (TG) curves for a single crystal of a new organic nonlinear optical material, urea-(d)tartaric acid (UDT) are reported. It is orthorhombic and belongs to the D 2 point group and P2 1 2 1 2 1 space group, a = 17.229(6)A, b = 9.824(3)A, c = 5.056(2)A, V = 855.77A 3 , Z = 4 and D m = 1.63 g/cm 3 . The second harmonic generation (SHG) of UDT, based on powder measurement, is three times higher than that of KDP. Its transparency range is from 240 to 1395 nm.
Kinetics of Photocationically Curable Formulations Involving Glycerol Diglycidyl Ether and Phenyl Glycidyl Ether
Kinetic analysis of formulations based on glycerol diglycidyl ether and phenyl glycidyl ether were carried out in the presence of sulfonium salt as initiator at 35 mW cm−2using photo differential scanning calorimeter and the final conversion was found to increase with an increase in phenyl glycidyl ether content. The effects of formulation monomer ratios at three different temperatures were studied. The variations in the observed kinetic parameters can be related to increase in mobility of reactive species with temperature, distance of counter ion from the propagating cationic center, as well as extent of crosslinking reaction which controlled the course and duration of the reaction. The applicability of autocatalytic kinetic model was also evaluated and the system underwent early gelation and the activation energy decreased with an increase in phenyl glycidyl ether content. Analysis of stable photocured films containing glycerol diglycidyl ether and phenyl glycidyl ether showed better thermal stability than rigid films obtained with glycerol diglycidyl ether.