The second dress is of Queen Juliana who was inaugurated in 1948, she was the only child of Queen Wilhelmina and Prince Hendrik. After 58 years Wilhelmina abdicated at September 6. She felt old and tired after 5 years living in excile in London during WWII and assigned the throne to Juliana who was 39 years old at that time.
Here a picture of Juliana with her family in the dress. It was made of blue-purple silk-jersey by Swiss designer Edwin Dolder. At the right you see her eldest daughter Beatrix who would be the next Queen. In the first photo you can see her dress with the furcoat behind Juliana's dress.
I found a better picture on the internet of the dresses of Princesses Beatrix and her sister Irene. They were made of satin and lace in pastel colours, the right one was light blue and the other one pink.
And a last picture of Queen Juliana and her husband Prince Bernhard during the inauguration.