  We perform return interval analysis of 1-min {\em{realized volatility}}
defined by the sum of absolute high-frequency intraday returns for the Shanghai
Stock Exchange Composite Index (SSEC) and 22 constituent stocks of SSEC. The
scaling behavior and memory effect of the return intervals between successive
realized volatilities above a certain threshold $q$ are carefully investigated.
In comparison with the volatility defined by the closest tick prices to the
minute marks, the return interval distribution for the realized volatility
shows a better scaling behavior since 20 stocks (out of 22 stocks) and the SSEC
pass the Kolmogorov-Smirnov (KS) test and exhibit scaling behaviors, among
which the scaling function for 8 stocks could be approximated well by a
stretched exponential distribution revealed by the KS goodness-of-fit test
under the significance level of 5%. The improved scaling behavior is further
confirmed by the relation between the fitted exponent $\gamma$ and the
threshold $q$. In addition, the similarity of the return interval distributions
for different stocks is also observed for the realized volatility. The
investigation of the conditional probability distribution and the detrended
fluctuation analysis (DFA) show that both short-term and long-term memory
exists in the return intervals of realized volatility.
