In this thesis, ultrafast dynamics of rhodamine B (C28H31ClN2O3) was studied by measuring time-resolved absorption changes using ultrafast transient absorption spectroscopy technique. In addition, birefringence induced by Kerr effect was studied in benzene and a 50:50 mixture of water and acetonitrile (C2H3N). Rhodamine B molecules dissolved in acetonitrile were excited by femtosecond pulses with the wavelength of 267nm (pump pulse) while their absorption as a function of time was tested with the probe pulses. Probe pulse spectrum was supercontinuum generated in calcium-fluoride (CaF2) crystal. Resulting signal consisted of positive and negative contribution. Positive contribution of the signal was caused by excited state absorption in which the molecules were excited by the pump beam. Negative contribution of the signal was caused by stimulated emission and ground state bleach which was concluded by observation of emission and absorption spectrum of rhodamine B. Spectral and temporal characteristics of probe pulses were studied by measurements of birefringence induced by Kerr effect. It was concluded that the probe pulses were significantly broadened in time in comparison to the fundamental pulses and also, positive chirp was present in probe pulses. In addition to above mentioned results, supercontinua generated in sapphire and CaF2 crystals were shown. Obtained results proved the functionality of the used experimental setup which will be used for future research and ultrafast transient absorption measurements of many different samples.