  We present evolutionary calculations for the size and aromatization degree
distributions of interstellar dust grains, driven by their destruction by
radiation, collisions with gas particles, and shattering due to grain-grain
collisions. Based on these calculations we model dust emission spectra. The
initial grain size distribution play the important role in the evolution of an
ensemble of dust particles. Radiation in the considered intensity range mostly
aromatizes grains. The smallest grains are mainly destructed via sputtering by
collisions with gas particles. There are no grains smaller than 20~\AA\ in the
medium at relative gas-dust velocities more than 50~km/s, which is typical for
shocks in supernova remnants. The IR emission spectrum changes significantly
due to the dust evolution depending on the adopted grain properties, in
particular, on the energy of the C--C bonds ($E_0$). Aromatic bands in the
near-IR (2--15~$\mu$m) are absent, if $E_0$ is low, even when the medium
properties correspond to the average interstellar medium in our Galaxy. As in
reality these bands are observed, high $E_0$ values are more preferable. We
consider dependence of the emission intensity ratios for various photometric
bands on the medium properties. The aromatization degree of small grains shows
up most strongly in the $I_{3.4}/I_{11.3}$ intensity ratio while the fraction
of aromatic grains in the total dust mass influences the $I_{3.3}/I_{70+160}$
ratio.
