You may know that the Mongols under Chinggis Khaan implemented a military system based on 10s, i.e. a decimal set of units. However, the Mongols tried to implement a decimal system of time. It worked well for day-to-day time, with daylight and night-time divided into arwan-tsag (10-hour), or 10 watches, and then each ‘hour’ divided into divisions of 10 and 100, arwiin-tsag and zyynii-tsag, however it didn’t work well going to months, simply because the moon is rather recalcitrant. With the fading of the great Mongolian empire, it gradually fell out of use. A 100th of a 10-hour is roughly 43 seconds, about the time it took a standard Mongolian horse-archer to put 10 arrows in the air.

Sources: Б. Мөнхбаатар, Чингис Хааны үеийн хэмжээ ба цаг (Measurements and Time in the era of Chingis Khan), Ulaanbaatar 2010. Also see Д. Алтансүх, Монгол их улсын цэргийн яанзлал (Military organisation of the Great Mongolian Empire), Ulaanbaatar, 1985.

Edit: Just acknowledging that this comment was part of the 2014 /r/AskHistorians April Fool's Prank, and was entirely fabricated.

It did change during the French Revolution, as the rest of the metric system was introduced. The Revolutionary calendar was reasonably successful within the French Empire, but decimal time never was seriously implemented. And after the end of the French Empire the revolutionary calendar was largely forgotten.

One reason I could see for this is that length and weight, the main other measurements in use back then, are properties of objects. It is relatively easy to use multiple systems of length or weight side by side, for various objects. But time organizes ideally all events, and to use different systems side by side defeats all purpose of calendar and clock.

It is interesting to note that except some minor alterations to the calendar, calendars and the units of time have never been altered in the West at all, except for this experiment in the French Revolution.