  We present seven epochs between October 1999 and November 2007 of high
resolution VLT/UVES echelle spectra of the ejecta-ring collision of SN 1987A.
The fluxes of most of the narrow lines from the unshocked gas decreased by a
factor of 2-3 during this period, consistent with the decay from the initial
ionization by the shock break-out. However, [O III] in particular shows an
increase up to day ~6800. This agrees with radiative shock models where the
pre-shocked gas is heated by the soft X-rays from the shock. The line emission
from the shocked gas increases rapidly as the shock sweeps up more gas. We find
that the neutral and high ionization lines follow the evolution of the Balmer
lines roughly, while the intermediate ionization lines evolve less rapidly. Up
to day ~6800, the optical light curves have a similar evolution to that of the
soft X-rays. The break between day 6500 and day 7000 for [O III] and [Ne III]
is likely due to recombination to lower ionization levels. Nevertheless, the
evolution of the [Fe XIV] line, as well as the lines from the lowest ionization
stages, continue to follow that of the soft X-rays, as expected. There is a
clear difference in the line profiles between the low and intermediate
ionization lines, and those from the coronal lines at the earlier epochs. This
shows that these lines arise from regions with different physical conditions,
with at least a fraction of the coronal lines coming from adiabatic shocks. At
later epochs the line widths of the low ionization lines, however, increase and
approach those of the high ionization lines of [Fe X-XIV]. The H-alpha line
profile can be traced up to ~500 km/s at the latest epoch. This is consistent
with the cooling time of shocks propagating into a density of (1-4)x10^4 cm-3.
