We present the performances of two 92% enriched $^{130}$TeO$_2$ crystals operated as thermal bolometers in view of a next generation experiment to search for neutrinoless double beta decay of $^{130}$Te. The crystals, 435 g each, show an energy resolution, evaluated at the 2615 keV $gamma$-line of $^{208}$Tl, of 6.5 and 4.3 keV FWHM. The only observable internal radioactive contamination arises from $^{238}$U (15 and 8 $mu$Bq/kg, respectively). The internal activity of the most problematic nuclei for neutrinoless double beta decay, $^{226}$Ra and $^{228}$Th, are both evaluated as $<$3.1 $mu$Bq/kg for one crystal and $<$2.3 $mu$Bq/kg for the second. Thanks to the readout of the weak Cherenkov light emitted by $beta/gamma$ particles by means of Neganov-Luke bolometric light detectors we were able to perform an event-by-event identification of $beta/gamma$ events with a 95% acceptance level, while establishing a rejection factor of 98.21% and 99.99% for $alpha$ particles.
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