A vibrational analysis using FTIR and Raman spectroscopies was carried out on pure liquid t-butyl alcohol (TBA) in the range of temperatures 15 <= t <= 70 degrees C. The whole range of molar fractions for TBA in 2,2'dimethylbutane (2,2'DMB) was also explored and compared with the t dependence of pure alcohol properties. Temperature and composition dependence of vibrational spectra were reproduced by simultaneous fitting of IR and Raman OH-stretching band contours by using harmonic frequencies and intensities derived from ab initio calculations for the various hydrogen-bonded structures. Adopting this fitting procedure, size and shape distributions of H-bonding aggregates have been derived, thus giving a quantitative description of balancing factors between hydrophilic and hydrophobic interactions in this liquid system.