They have a duration of 5 seconds which refreshes upon gaining a new blitz charge. All Blitz charges fall off after not gaining a charge for 5 seconds.
Ascendancy passive skills
There are Ascendancy passive skills that affect Blitz Charges.
|Berserker||Blitz||Gain a Blitz Charge on Critical Strike|
2% more Attack Speed per Blitz Charge
10% reduced Critical Strike Chance per Blitz Charge
+20 to Maximum Blitz Charges