Generally speaking throughout Hitler's book Mein Kampf he generally refers to Slavs in negative connotations and how the Germanization of Slavs was akin to trying to Germanize a Black man or Chinese man and only result in de-Germanization. This was specifically in regards to events in Austria.

Online English Translation of Mein Kampf

Within that you can find Hitler referring to the Intellectuals of Russia as not being Slavic, and that the masses of Russia had little mental and morale levels.

The real organizer of the Revolution and the actual wire-puller behind it, the international Jew, had sized up the situation correctly. The German people were not yet ripe to be drawn into the blood swamp of Bolshevism, as the Russian people had been drawn. And that was because there was a closer racial union between the intellectual classes in Germany and the manual workers, and also because broad social strata were permeated with cultured people, such as was the case also in the other States of Western Europe; but this state of affairs was completely lacking in Russia. In that country the intellectual classes were mostly not of Russian nationality, or at least they did not have the racial characteristics of the Slav. The thin upper layer of intellectuals which then existed in Russia might be abolished at any time, because there was no intermediate stratum connecting it organically with the great mass of the people. There the mental and moral level of the great mass of the people was frightfully low.

Direct mentions of German superiority over Russian Slavs

Destiny itself seems to wish to point out the way for us here. In delivering Russia over to Bolshevism, Fate robbed the Russian people of that intellectual class which had once created the Russian State and were the guarantee of its existence. For the Russian State was not organized by the constructive political talent of the Slav element in Russia, but was much more a marvellous exemplification of the capacity for State-building possessed by the Germanic element in a race of inferior worth. Thus were many powerful Empires created all over the earth. More often than once inferior races with Germanic organizers and rulers as their leaders became formidable States and continued to exist as long as the racial nucleus remained which had originally created each respective State. For centuries Russia owed the source of its livelihood as a State to the Germanic nucleus of its governing class...

So perhaps "hate" isn't a 100% correct word, but he at minimum didn't hold Slavs in high-regard or even neutral-regard like he did with various other "races" such as the English, Americans, Greek (at least ancient Greek), etc.

Hitler as well as many other Nazis also frequently used the term "Untermensch" (literally under man) frequently when referring to Poles, Serbs and Russians along with a myriad of other ethnic-groups.

To properly answer your question make yourself familiar with Generalplan Ost. The Nazis planned to starve to death or otherwise eradicate millions of ethnic Slavs in Eastern and Central Europe in their nefarious pursuit of Lebensraum. There is absolutely no doubt about Hitler's feelings towards the Slavic people.

If this area of history interests you, I would recommend reading the following titles as a starting point:

Ostkrieg: Hitler's War of Extermination in the East by Stephen G. Fritz.

Bloodlands: Europe Between Hitler and Stalin by Timothy Snyder.