CRJ-700 First Officer reported during climbout the Captain's side windshield cracked.

Narrative

Continuously cracking windshield on Captain windscreen in-flight.I was PF and after taking off from ZZZ; I noticed at 3;000 feet that there was a long vertical crack on the Captain's windscreen. I asked Captain to confirm and he examined the windscreen and confirmed that it was a crack. I asked him if we should declare an emergency and return to the departure airport. He declined to declare and stated that we should continue and he would monitor the crack. Captain began reviewing QRH. While climbing through 16;000 at 290 we heard a big pop. I saw that the Captain's windscreen now had a large inverted 'C' shaped crack was connected to the original; vertical crack. I immediately stopped climbing to our assigned altitude by pressing 'ALT' on the FCP and simultaneously reduced power so our speed was at 250 kts. I asked the Captain if we should declare an emergency. He decided not to declare so I asked him to advise ATC immediately that we were stopping our climb and slowing. Captain advised ATC accordingly. ATC asked if he wanted to declare an emergency. Captain declined but advised ATC that we were leveling off and slowing to 250kts. He also instructed me to level off and set 16;000 as our altitude and maintain 250kts. Captain finished reading QRH to himself and stated that QRH review was complete. ATC asked us for the number of souls and fuel onboard and the Captain provided it. We began descending for ZZZ1 and at about 12;000 we heard some more cracking towards the left corner of the Captain's windscreen. I asked the Captain if we should have the flight attendants take their seats. He said it wasn't necessary and that the pressurization was holding fine in the cabin. (He had been diligently watching the cabin pressurization during the entire situation). During final approach for ILS XXL at ZZZ1 we encountered some weather. As I waited for the Captain to make the 1000-foot call; I noticed that something was coming through the window. I annunciated the 1000 foot call for him. It looked like he had some very small glass fragments in his hands. I asked him if he wanted me to declare an emergency. He declined. I made the 500 foot call for him and we landed without any further issues. I had approximately 210 hours in the CRJ at the time of the incident and the CRJ is my first experience with any pressurized aircraft. My Captain has been a pilot with the company for more than 20 years. I learned a lot during the situation from him.