P. Ziobrowski

Phase transition study of 1,4-butanediol dimethacrylate by the optical Kerr effect and Brillouin light scattering☆

Abstract We report the results of a temperature study of the optical Kerr effect in 1,4-butanediol dimethacrylate (BDM) revealing a phase transition in the temperature range from 295 to 302 K. Using the Brillouin light scattering method we have also studied the temperature behaviour of the sound velocity and the elasto-optic of BDM. The above temperature dependences display a characteristic discontinuity at about 298 K.

Molecular dynamics of poly(ethylene glycol)s studied by optical Kerr effect and Brillouin spectroscopy

The optical Kerr effect and Brillouin scattering study of a series of poly(ethylene glycol)s (PEGs) in the function of temperature and molecular weight (MW) have been performed. The obtained results enabled us to determine some macroscopic and microscopic parameters (such as molecular Kerr constant, hypersonic velocity, adiabatic compressibility), of the compounds investigated. The values of these parameters were found to depend strongly on both temperature and PEGs MW. Analysis of the results indicates on the presence of molecular interactions leading to formation of molecular aggregates. The increase in the MW leads to folding of PEG chains and to formation of statistical coils.

Brillouin study of photopolymerization process of two-monomer systems

The results of Brillouin scattering investigations of two-component system: 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane/polyethylene glycol methacrylate (bis-GMA/PEGMM) containing 0, 30, 50, 70, 85 and 100 mol% of PEGMM are presented. For the first time the Brillouin spectroscopy was used to monitor the progress of the polymerization process. The polymerization was initiated by ultraviolet radiation (λ=365 nm), at temperature 20°C and 40°C. Some of the physical parameters characteristic for this system such as velocity V, adiabatic compressibility β(ad) and attenuation coefficient α of the acoustic waves have been estimated from Brillouin spectra as a functions of the polymerization time. The obtained results have been discussed in terms of changes of the elastic properties of the two-component system occurring during polymerization process and their dependence on bis-GMA/PEGMM system composition.

Study of Brillouin scattering and optical Kerr effect in 2,2′-thiobisethanol dimethacrylate

Abstract In this work, we report the results of a temperature study of Brillouin light scattering and the optical Kerr effect in 2,2′-thiobisethanol dimethacrylate (TEDM). Using these methods, we studied the temperature behaviour of the sound velocity and optical Kerr constant in the temperature range 283–323 K. The temperature dependence observed by two independent optical methods displays a characteristic discontinuity at about 296–303 K, which may point to a change in intermolecular interaction in the compound investigated. The results presented are consistent with those obtained previously for the optical Kerr effect and Raman and Brillouin scattering of butane-1,4-diol dimethacrylate (BDM).

Elastic properties of n-ZnSe single crystals by Brillouin scattering

Values of the elastic constants C11, C12, and C44 of the n-ZnSe single crystals with different free carrier concentration were studied using Brillouin light scattering method. It has been shown that the results obtained from Brillouin scattering study are in good agreement with the data obtained earlier from Raman scattering experiment. We also present the influence of the annealing procedure on the velocity of the elastic waves propagating in (110) and (111) planes for n-ZnSe single crystals. The large effect of the annealing procedure of the n-ZnSe single crystals in liquid zinc on their elastic properties has been discussed using theory proposed by Martin.

Brillouin scattering in n-ZnSe single crystals with different free-carrier concentration

We present the influence of the free carrier concentration on the elastic properties of n-ZnSe single crystals using Brillouin light scattering method. For this purpose the Brillouin polarized spectra of n-ZnSe single crystals with different free carrier concentration were measured at room temperature. It has been shown that the value of the velocity of the elastic waves propagating in n-ZnSe single crystals strongly depends on the free carriers concentration. The large effect of the annealing of n-ZnSe single crystals on their elastic properties is also discussed.

Elastic properties of some selected two-monomer systems as studied by Brillouin spectroscopy.

We present results obtained by Brillouin scattering method for four two-component systems comprising of a high viscosity monomer and a low viscosity monomer. The monomers used were crosslinking (divinyl) or linear (monovinyl) ones. The investigated systems were: divinyl/divinyl-bis-GMA/TEGDM; divinyl/monovinyl-bis-GMA/PEGMM; monovinyl/divinyl-bis-MGMA/TEGDM and monovinyl/monovinyl-bis-MGMA/PEGMM; they were formulated at various molar ratios. The measurements have been performed in temperature range 293-353 K. The following physical parameters characterizing the investigated systems were estimated: hypersonic velocity V, attenuation coefficient α and adiabatic compressibility β, all as a function of temperature and monomer molar ratio. The obtained results have been discussed in terms of the influence of the system composition and viscosity on their elastic properties. Speed of changes of the adiabatic compressibility β as derivative have been also discussed in terms of both, the temperature as well as the component of molar ratio.

Investigation of the local structure of selected dimethacrylates by Brillouin light scattering

Temperature dependence of Brillouin light scattering in selected dimethacrylates has been studied. For the compounds studied, being multifunctional monomers, the values of hypersound speed have been determined. It has been established that with increasing temperature the hypersound speed decreases for all substances studied.

Elastic and elasto-optic properties of Zn1-xBexSe mixed crystals by Brillouin scattering method

In this paper we report experimental results concerning the elastic and elastooptic properties of Zn1-xBexSe mixed crystals grown by high pressure Bridgman technique. Using Brillouin scattering method some of the elastic and elastooptic constants of Zn1-xBexSe crystals with different Be content have been determined at room temperature. It has been revealed that the elastic and elastooptic properties strongly depend on the content of Be.

Study of the elastooptic properties of n-ZnSe single crystals by Brillouin scattering

The values of the elasto-optic constants: p11, p12, and p44 of n-type ZnSe single crystals with different free carrier concentrations were studied using Brillouin light scattering method. It has been shown that the value of the elasto-optic constants pij of ZnSe single crystals strongly depends on the free carrier concentration. Obtained results are also discussed in terms of the existence of twins, native defects, and uncontrolled dopants which may arise in the crystal during the growth process.